Advertisement SpringerLink (BUTTON) Search * Log in Search SpringerLink ____________________ (BUTTON) Search Table 2 The average Group Number (GN) for each year 1610âââ2015. The estimated relative ± error in % is used to indicate expected low and high limits of the Group number. The table is also available in electronic form in the Supplemental Material at www.leif.org/research/ . From: Reconstruction of the Sunspot Group Number: The Backbone Method Year Low GN Mean GN High GN Error % Year Low GN Mean GN High GN Error % 1610.5 1.72 2.64 3.56 35 1611.5 3.43 5.28 7.13 35 1612.5 6.86 10.56 14.26 35 1613.5 5.15 7.92 10.69 35 1614.5 4.58 7.04 9.50 35 1615.5 5.72 8.80 11.88 35 1616.5 4.58 7.04 9.50 35 1617.5 0.57 0.88 1.19 35 1618.5 0.57 0.88 1.19 35 1619.5 0.57 0.88 1.19 35 1620.5 0.57 0.88 1.19 35 1621.5 0.57 0.88 1.19 35 1622.5 0.57 0.88 1.19 35 1623.5 0.57 0.88 1.19 35 1624.5 1.14 1.76 2.38 35 1625.5 5.72 8.80 11.88 35 1626.5 4.00 6.16 8.32 35 1627.5 1.72 2.64 3.56 35 1628.5 1.72 2.64 3.56 35 1629.5 1.72 2.64 3.56 35 1630.5 0.03 0.05 0.08 50 1631.5 0.57 0.88 1.19 35 1632.5 0.03 0.05 0.08 50 1633.5 2.29 3.52 4.75 35 1634.5 1.72 2.64 3.56 35 1635.5 1.14 1.76 2.38 35 1636.5 1.11 1.70 2.30 35 1637.5 1.17 1.80 2.43 35 1638.5 1.14 1.76 2.38 35 1639.5 0.57 0.88 1.19 35 1640.5 0.57 0.88 1.19 35 1641.5 1.04 1.60 2.16 35 1642.5 1.72 2.64 3.56 35 1643.5 2.29 3.52 4.75 35 1644.5 2.86 4.40 5.94 35 1645.5 0.57 0.88 1.19 35 1646.5 0.26 0.40 0.54 35 1647.5 0.13 0.20 0.27 35 1648.5 0.03 0.05 0.08 50 1649.5 0.03 0.05 0.08 50 1650.5 0.20 0.30 0.41 35 1651.5 0.65 1.00 1.35 35 1652.5 1.14 1.76 2.38 35 1653.5 1.72 2.64 3.56 35 1654.5 2.29 3.52 4.75 35 1655.5 0.57 0.88 1.19 35 1656.5 0.57 0.88 1.19 35 1657.5 0.57 0.88 1.19 35 1658.5 0.03 0.05 0.08 50 1659.5 0.03 0.05 0.08 50 1660.5 1.14 1.76 2.38 35 1661.5 0.57 0.88 1.19 35 1662.5 0.03 0.05 0.08 50 1663.5 0.03 0.05 0.08 50 1664.5 0.03 0.05 0.08 50 1665.5 0.03 0.05 0.08 50 1666.5 0.03 0.05 0.08 50 1667.5 0.03 0.05 0.08 50 1668.5 0.03 0.05 0.08 50 1669.5 0.03 0.05 0.08 50 1670.5 0.03 0.05 0.08 50 1671.5 0.57 0.88 1.19 35 1672.5 0.57 0.88 1.19 35 1673.5 0.03 0.05 0.08 50 1674.5 0.57 0.88 1.19 35 1675.5 0.03 0.05 0.08 50 1676.5 1.14 1.76 2.38 35 1677.5 0.57 0.88 1.19 35 1678.5 0.57 0.88 1.19 35 1679.5 0.57 0.88 1.19 35 1680.5 1.14 1.76 2.38 35 1681.5 0.57 0.88 1.19 35 1682.5 0.57 0.88 1.19 35 1683.5 0.03 0.05 0.08 50 1684.5 1.14 1.76 2.38 35 1685.5 0.03 0.05 0.08 50 1686.5 1.72 2.64 3.56 35 1687.5 1.14 1.76 2.38 35 1688.5 1.14 1.76 2.38 35 1689.5 0.57 0.88 1.19 35 1690.5 0.03 0.05 0.08 50 1691.5 0.03 0.05 0.08 50 1692.5 0.03 0.05 0.08 50 1693.5 0.03 0.05 0.08 50 1694.5 0.03 0.05 0.08 50 1695.5 0.57 0.88 1.19 35 1696.5 0.03 0.05 0.08 50 1697.5 0.03 0.05 0.08 50 1698.5 0.03 0.05 0.08 50 1699.5 0.03 0.05 0.08 50 1700.5 1.45 1.76 2.07 18 1701.5 1.45 1.76 2.07 18 1702.5 0.73 0.88 1.03 18 1703.5 2.18 2.64 3.10 18 1704.5 3.63 4.40 5.17 18 1705.5 4.36 5.28 6.20 18 1706.5 2.90 3.52 4.14 18 1707.5 2.18 2.64 3.10 18 1708.5 1.45 1.76 2.07 18 1709.5 2.18 2.64 3.10 18 1710.5 0.73 0.88 1.03 18 1711.5 0.04 0.05 0.06 20 1712.5 0.04 0.05 0.06 20 1713.5 0.73 0.88 1.03 18 1714.5 1.45 1.76 2.07 18 1715.5 2.90 3.52 4.14 18 1716.5 5.81 7.04 8.27 18 1717.5 3.63 4.40 5.17 18 1718.5 3.63 4.40 5.17 18 1719.5 5.08 6.16 7.24 18 1720.5 6.53 7.92 9.31 18 1721.5 6.53 7.92 9.31 18 1722.5 1.45 1.76 2.07 18 1723.5 0.73 0.88 1.03 18 1724.5 2.18 2.64 3.10 18 1725.5 2.18 2.64 3.10 18 1726.5 7.26 8.80 10.34 18 1727.5 5.81 7.04 8.27 18 1728.5 9.44 11.44 13.44 18 1729.5 6.53 7.92 9.31 18 1730.5 7.26 8.80 10.34 18 1731.5 5.03 6.10 7.17 18 1732.5 2.18 2.64 3.10 18 1733.5 0.73 0.88 1.03 18 1734.5 0.91 1.10 1.29 18 1735.5 2.90 3.52 4.14 18 1736.5 6.53 7.92 9.31 18 1737.5 2.18 2.64 3.10 18 1738.5 2.90 3.52 4.14 18 1739.5 6.41 7.77 9.13 17 1740.5 4.79 5.80 6.82 18 1741.5 2.18 2.64 3.10 18 1742.5 2.29 2.78 3.27 17 1743.5 1.49 1.81 2.12 17 1744.5 2.34 2.84 3.33 17 1745.5 4.14 5.02 5.90 18 1746.5 6.17 7.48 8.78 17 1747.5 7.70 9.33 10.97 18 1748.5 8.03 9.74 11.44 17 1749.5 6.58 7.97 9.37 18 1750.5 7.27 8.82 10.36 17 1751.5 3.99 4.84 5.68 17 1752.5 3.40 4.13 4.85 17 1753.5 2.31 2.80 3.29 17 1754.5 1.07 1.30 1.52 17 1755.5 0.70 0.85 1.00 17 1756.5 1.05 1.27 1.49 17 1757.5 3.00 3.63 4.27 18 1758.5 3.49 4.23 4.97 18 1759.5 4.19 5.07 5.96 18 1760.5 4.28 5.19 6.10 18 1761.5 6.85 8.30 9.75 18 1762.5 4.98 6.04 7.10 18 1763.5 3.44 4.17 4.90 17 1764.5 4.24 5.14 6.04 18 1765.5 1.12 1.36 1.59 17 1766.5 1.06 1.29 1.51 17 1767.5 3.83 4.65 5.46 17 1768.5 6.52 7.90 9.29 18 1769.5 8.79 10.65 12.52 18 1770.5 8.07 9.78 11.49 17 1771.5 7.10 8.60 10.11 18 1772.5 5.52 6.69 7.86 17 1773.5 2.89 3.50 4.11 18 1774.5 3.18 3.86 4.54 18 1775.5 1.66 2.01 2.36 17 1776.5 2.09 2.53 2.97 18 1777.5 6.14 7.44 8.74 18 1778.5 9.92 12.03 14.13 17 1779.5 8.90 10.78 12.67 18 1780.5 7.27 8.81 10.35 17 1781.5 6.94 8.41 9.88 17 1782.5 2.71 3.29 3.86 17 1783.5 2.44 2.95 3.47 18 1784.5 0.44 0.53 0.62 17 1785.5 1.43 1.73 2.04 18 1786.5 6.90 8.36 9.83 18 1787.5 9.77 11.84 13.91 18 1788.5 9.20 11.15 13.10 17 1789.5 8.02 9.72 11.43 18 1790.5 6.61 8.01 9.42 18 1791.5 5.51 6.68 7.85 18 1792.5 4.95 6.01 7.06 17 1793.5 1.98 2.40 2.82 18 1794.5 3.46 4.19 4.93 18 1795.5 1.42 1.73 2.03 17 1796.5 1.19 1.45 1.70 17 1797.5 0.59 0.71 0.84 18 1798.5 0.36 0.43 0.51 18 1799.5 0.54 0.66 0.78 18 1800.5 1.65 2.00 2.35 18 1801.5 3.92 4.74 5.55 17 1802.5 3.20 3.84 4.47 17 1803.5 3.37 4.01 4.65 16 1804.5 4.20 4.96 5.73 15 1805.5 3.30 3.88 4.46 15 1806.5 1.57 1.83 2.09 14 1807.5 1.51 1.75 2.00 14 1808.5 0.93 1.07 1.22 13 1809.5 0.49 0.57 0.64 13 1810.5 0.04 0.05 0.06 20 1811.5 0.28 0.32 0.36 12 1812.5 1.47 1.67 1.87 12 1813.5 2.19 2.48 2.77 12 1814.5 1.91 2.15 2.39 11 1815.5 2.33 2.61 2.90 11 1816.5 3.14 3.51 3.88 11 1817.5 2.87 3.20 3.53 10 1818.5 3.43 3.81 4.19 10 1819.5 3.39 3.75 4.12 10 1820.5 1.59 1.75 1.92 9 1821.5 1.64 1.80 1.97 9 1822.5 1.74 1.91 2.08 9 1823.5 0.83 0.91 0.99 9 1824.5 1.24 1.35 1.46 8 1825.5 2.19 2.39 2.59 8 1826.5 3.53 3.84 4.15 8 1827.5 4.49 4.87 5.25 8 1828.5 5.24 5.67 6.10 8 1829.5 5.90 6.38 6.86 7 1830.5 5.88 6.35 6.82 7 1831.5 4.22 4.55 4.88 7 1832.5 2.59 2.79 2.99 7 1833.5 0.97 1.04 1.11 7 1834.5 1.38 1.48 1.58 7 1835.5 4.59 4.91 5.23 7 1836.5 8.99 9.61 10.23 6 1837.5 10.60 11.32 12.04 6 1838.5 7.74 8.26 8.78 6 1839.5 6.58 7.01 7.44 6 1840.5 4.94 5.26 5.58 6 1841.5 2.62 2.78 2.94 6 1842.5 1.81 1.92 2.03 6 1843.5 0.71 0.75 0.79 6 1844.5 1.05 1.11 1.17 6 1845.5 2.97 3.14 3.31 6 1846.5 4.35 4.60 4.85 5 1847.5 6.69 7.07 7.45 5 1848.5 9.07 9.58 10.09 5 1849.5 8.45 8.92 9.39 5 1850.5 6.07 6.40 6.73 5 1851.5 6.12 6.45 6.78 5 1852.5 5.24 5.52 5.80 5 1853.5 3.94 4.15 4.36 5 1854.5 1.89 1.99 2.09 5 1855.5 0.73 0.77 0.81 5 1856.5 0.46 0.48 0.50 5 1857.5 2.52 2.65 2.78 5 1858.5 5.01 5.26 5.51 5 1859.5 8.46 8.88 9.30 5 1860.5 9.48 9.94 10.40 5 1861.5 7.73 8.10 8.47 5 1862.5 5.50 5.76 6.02 5 1863.5 4.73 4.96 5.19 5 1864.5 4.18 4.38 4.58 5 1865.5 2.55 2.67 2.79 4 1866.5 1.68 1.76 1.84 4 1867.5 0.78 0.82 0.86 4 1868.5 3.30 3.45 3.60 4 1869.5 6.75 7.06 7.37 4 1870.5 10.73 11.22 11.71 4 1871.5 9.81 10.25 10.69 4 1872.5 8.31 8.68 9.05 4 1873.5 5.74 5.99 6.24 4 1874.5 3.82 3.99 4.16 4 1875.5 1.75 1.83 1.91 4 1876.5 1.13 1.18 1.23 4 1877.5 0.95 0.99 1.03 4 1878.5 0.40 0.42 0.44 4 1879.5 0.73 0.76 0.79 4 1880.5 2.59 2.70 2.81 4 1881.5 4.43 4.62 4.81 4 1882.5 4.58 4.78 4.98 4 1883.5 5.09 5.31 5.53 4 1884.5 5.60 5.84 6.08 4 1885.5 4.45 4.64 4.83 4 1886.5 2.31 2.41 2.51 4 1887.5 1.30 1.35 1.40 4 1888.5 0.75 0.78 0.81 4 1889.5 0.58 0.60 0.62 4 1890.5 0.66 0.69 0.72 4 1891.5 3.42 3.56 3.70 4 1892.5 5.94 6.18 6.42 4 1893.5 7.42 7.73 8.04 4 1894.5 6.83 7.11 7.39 4 1895.5 5.27 5.49 5.71 4 1896.5 3.30 3.44 3.58 4 1897.5 2.51 2.61 2.71 4 1898.5 2.09 2.17 2.25 4 1899.5 1.05 1.09 1.13 4 1900.5 0.84 0.87 0.90 4 1901.5 0.26 0.27 0.28 4 1902.5 0.33 0.34 0.35 4 1903.5 1.77 1.84 1.91 4 1904.5 3.61 3.76 3.91 4 1905.5 4.35 4.52 4.69 4 1906.5 4.32 4.49 4.66 4 1907.5 4.57 4.75 4.93 4 1908.5 3.94 4.10 4.26 4 1909.5 3.36 3.49 3.62 4 1910.5 1.64 1.71 1.78 4 1911.5 0.63 0.66 0.69 4 1912.5 0.30 0.31 0.32 4 1913.5 0.13 0.13 0.13 4 1914.5 0.89 0.93 0.97 4 1915.5 3.37 3.50 3.63 4 1916.5 4.64 4.82 5.00 4 1917.5 7.60 7.90 8.20 4 1918.5 6.31 6.56 6.81 4 1919.5 5.24 5.45 5.66 4 1920.5 3.14 3.26 3.38 4 1921.5 2.12 2.20 2.28 4 1922.5 1.20 1.25 1.30 4 1923.5 0.56 0.58 0.60 4 1924.5 1.32 1.37 1.42 4 1925.5 3.70 3.85 4.00 4 1926.5 5.07 5.27 5.47 4 1927.5 5.72 5.95 6.18 4 1928.5 5.82 6.05 6.28 4 1929.5 5.19 5.39 5.59 4 1930.5 3.18 3.31 3.44 4 1931.5 1.96 2.04 2.12 4 1932.5 1.09 1.13 1.17 4 1933.5 0.54 0.56 0.58 4 1934.5 0.84 0.87 0.90 4 1935.5 3.18 3.31 3.44 4 1936.5 6.53 6.79 7.05 4 1937.5 9.02 9.37 9.72 4 1938.5 8.32 8.65 8.98 4 1939.5 7.46 7.75 8.04 4 1940.5 5.22 5.43 5.63 4 1941.5 3.56 3.70 3.84 4 1942.5 2.44 2.53 2.63 4 1943.5 1.17 1.21 1.26 4 1944.5 0.80 0.83 0.86 4 1945.5 2.67 2.78 2.88 4 1946.5 6.63 6.89 7.15 4 1947.5 9.75 10.13 10.51 4 1948.5 8.99 9.35 9.70 4 1949.5 8.96 9.31 9.66 4 1950.5 5.41 5.63 5.84 4 1951.5 4.10 4.26 4.42 4 1952.5 2.34 2.43 2.52 4 1953.5 1.09 1.13 1.17 4 1954.5 0.49 0.50 0.52 4 1955.5 2.78 2.89 3.00 4 1956.5 9.00 9.36 9.71 4 1957.5 11.77 12.23 12.69 4 1958.5 12.47 12.95 13.44 4 1959.5 10.46 10.87 11.28 4 1960.5 7.63 7.93 8.22 4 1961.5 3.78 3.93 4.07 4 1962.5 2.45 2.54 2.64 4 1963.5 1.90 1.97 2.05 4 1964.5 0.85 0.88 0.91 4 1965.5 1.16 1.21 1.25 4 1966.5 3.19 3.32 3.44 4 1967.5 6.81 7.07 7.34 4 1968.5 6.87 7.14 7.41 4 1969.5 7.00 7.27 7.54 4 1970.5 7.74 8.04 8.34 4 1971.5 5.28 5.49 5.69 4 1972.5 5.13 5.33 5.53 4 1973.5 2.84 2.95 3.06 4 1974.5 2.59 2.69 2.79 4 1975.5 1.14 1.19 1.23 4 1976.5 1.04 1.08 1.12 4 1977.5 2.22 2.31 2.40 4 1978.5 7.09 7.36 7.64 4 1979.5 10.93 11.36 11.78 4 1980.5 10.11 10.50 10.90 4 1981.5 9.93 10.32 10.71 4 1982.5 8.10 8.41 8.73 4 1983.5 4.83 5.02 5.21 4 1984.5 3.04 3.16 3.28 4 1985.5 1.13 1.18 1.22 4 1986.5 0.83 0.86 0.89 4 1987.5 1.84 1.92 1.99 4 1988.5 5.88 6.11 6.34 4 1989.5 9.70 10.07 10.45 4 1990.5 9.60 9.97 10.35 4 1991.5 9.69 10.07 10.44 4 1992.5 6.59 6.85 7.11 4 1993.5 3.87 4.02 4.17 4 1994.5 2.47 2.57 2.67 4 1995.5 1.43 1.49 1.54 4 1996.5 0.65 0.67 0.70 4 1997.5 1.55 1.61 1.67 4 1998.5 4.70 4.88 5.06 4 1999.5 6.64 6.90 7.16 4 2000.5 8.62 8.95 9.29 4 2001.5 8.85 9.20 9.54 4 2002.5 8.56 8.90 9.23 4 2003.5 5.19 5.39 5.59 4 2004.5 3.39 3.52 3.66 4 2005.5 2.50 2.60 2.70 4 2006.5 1.47 1.52 1.58 4 2007.5 0.76 0.79 0.82 4 2008.5 0.31 0.32 0.33 4 2009.5 0.39 0.40 0.42 4 2010.5 1.61 1.67 1.74 4 2011.5 4.62 4.80 4.98 4 2012.5 4.90 5.09 5.28 4 2013.5 5.56 5.78 5.99 4 2014.5 6.38 6.63 6.87 4 2015.5 4.76 4.94 5.13 4