%  Sunspot data from 
%  ftp://ftp.ngdc.noaa.gov/STP/SOLAR_DATA/SUNSPOT_NUMBERS/YEARLY.PLT
%  Format:
%    Column 1: year   (1700-2006)
%    Column 2: sunspot number
%
% Quoting from NOAA:
% 
% In 1848 the Swiss astronomer Johann Rudolph Wolf introduced a daily measure-
% ment of sunspot number.  His method, which is still used today, counts the 
% total number of spots visible on the face of the sun and the number of groups 
% into which they cluster, because neither quantity alone satisfactorily meas-
% ures sunspot activity.
% 
% An observer computes a daily sunspot number by multiplying the number of
% groups he sees by ten and then adding this product to his total count of in-
% dividual spots.  Results, however, vary greatly, since the measurement strong-
% ly depends on observer interpretation and experience and on the stability of 
% the Earth's atmosphere above the observing site.  Moreover, the use of Earth 
% as a platform from which to record these numbers contributes to their varia-
% bility, too, because the sun rotates and the evolving spot groups are distrib-
% uted unevenly across solar longitudes.  To compensate for these limitations,
% each daily international number is computed as a weighted average of measure-
% ments made from a network of cooperating observatories.
% 
% Today, much more sophisticated measurements of solar activity are made 
% routinely,but none has the link with the past that sunspot numbers have.

x=[
1700   5
1701  11
1702  16
1703  23
1704  36
1705  58
1706  29
1707  20
1708  10
1709   8
1710   3
1711   0
1712   0
1713   2
1714  11
1715  27
1716  47
1717  63
1718  60
1719  39
1720  28
1721  26
1722  22
1723  11
1724  21
1725  40
1726  78
1727 122
1728 103
1729  73
1730  47
1731  35
1732  11
1733   5
1734  16
1735  34
1736  70
1737  81
1738 111
1739 101
1740  73
1741  40
1742  20
1743  16
1744   5
1745  11
1746  22
1747  40
1748  60
1749  80.9
1750  83.4
1751  47.7
1752  47.8
1753  30.7
1754  12.2
1755   9.6
1756  10.2
1757  32.4
1758  47.6
1759  54.0
1760  62.9
1761  85.9
1762  61.2
1763  45.1
1764  36.4
1765  20.9
1766  11.4
1767  37.8
1768  69.8
1769 106.1
1770 100.8
1771  81.6
1772  66.5
1773  34.8
1774  30.6
1775   7.0
1776  19.8
1777  92.5
1778 154.4
1779 125.9
1780  84.8
1781  68.1
1782  38.5
1783  22.8
1784  10.2
1785  24.1
1786  82.9
1787 132.0
1788 130.9
1789 118.1
1790  89.9
1791  66.6
1792  60.0
1793  46.9
1794  41.0
1795  21.3
1796  16.0
1797   6.4
1798   4.1
1799   6.8
1800  14.5
1801  34.0
1802  45.0
1803  43.1
1804  47.5
1805  42.2
1806  28.1
1807  10.1
1808   8.1
1809   2.5
1810   0.0
1811   1.4
1812   5.0
1813  12.2
1814  13.9
1815  35.4
1816  45.8
1817  41.1
1818  30.1
1819  23.9
1820  15.6
1821   6.6
1822   4.0
1823   1.8
1824   8.5
1825  16.6
1826  36.3
1827  49.6
1828  64.2
1829  67.0
1830  70.9
1831  47.8
1832  27.5
1833   8.5
1834  13.2
1835  56.9
1836 121.5
1837 138.3
1838 103.2
1839  85.7
1840  64.6
1841  36.7
1842  24.2
1843  10.7
1844  15.0
1845  40.1
1846  61.5
1847  98.5
1848 124.7
1849  96.3
1850  66.6
1851  64.5
1852  54.1
1853  39.0
1854  20.6
1855   6.7
1856   4.3
1857  22.7
1858  54.8
1859  93.8
1860  95.8
1861  77.2
1862  59.1
1863  44.0
1864  47.0
1865  30.5
1866  16.3
1867   7.3
1868  37.6
1869  74.0
1870 139.0
1871 111.2
1872 101.6
1873  66.2
1874  44.7
1875  17.0
1876  11.3
1877  12.4
1878   3.4
1879   6.0
1880  32.3
1881  54.3
1882  59.7
1883  63.7
1884  63.5
1885  52.2
1886  25.4
1887  13.1
1888   6.8
1889   6.3
1890   7.1
1891  35.6
1892  73.0
1893  85.1
1894  78.0
1895  64.0
1896  41.8
1897  26.2
1898  26.7
1899  12.1
1900   9.5
1901   2.7
1902   5.0
1903  24.4
1904  42.0
1905  63.5
1906  53.8
1907  62.0
1908  48.5
1909  43.9
1910  18.6
1911   5.7
1912   3.6
1913   1.4
1914   9.6
1915  47.4
1916  57.1
1917 103.9
1918  80.6
1919  63.6
1920  37.6
1921  26.1
1922  14.2
1923   5.8
1924  16.7
1925  44.3
1926  63.9
1927  69.0
1928  77.8
1929  64.9
1930  35.7
1931  21.2
1932  11.1
1933   5.7
1934   8.7
1935  36.1
1936  79.7
1937 114.4
1938 109.6
1939  88.8
1940  67.8
1941  47.5
1942  30.6
1943  16.3
1944   9.6
1945  33.2
1946  92.6
1947 151.6
1948 136.3
1949 134.7
1950  83.9
1951  69.4
1952  31.5
1953  13.9
1954   4.4
1955  38.0
1956 141.7
1957 190.2
1958 184.8
1959 159.0
1960 112.3
1961  53.9
1962  37.6
1963  27.9
1964  10.2
1965  15.1
1966  47.0
1967  93.8
1968 105.9
1969 105.5
1970 104.5
1971  66.6
1972  68.9
1973  38.0
1974  34.5
1975  15.5
1976  12.6
1977  27.5
1978  92.5
1979 155.4
1980 154.6
1981 140.4
1982 115.9
1983  66.6
1984  45.9
1985  17.9
1986  13.4
1987  29.4
1988 100.2
1989 157.6
1990 142.6
1991 145.7
1992  94.3
1993  54.6
1994  29.9
1995  17.5
1996   8.6
1997  21.5
1998  64.3
1999  93.3
2000 119.6
2001 111.0
2002 104.0
2003  63.7
2004  40.4
2005  29.8
2006  15.2]

