Year Years
1800 25.5
1801 25.5
1802 25.5
1803 25.5
1804 25.5
1805 25.5
1806 25.5
1807 25.5
1808 25.5
1809 25.5
1810 25.5
1811 25.5
1812 25.5
1813 25.5
1814 25.5
1815 25.5
1816 25.5
1817 25.5
1818 25.5
1819 25.5
1820 25.5
1821 25.5
1822 25.5
1823 25.5
1824 25.5
1825 25.5
1826 25.5
1827 25.5
1828 25.5
1829 25.5
1830 25.5
1831 25.5
1832 25.5
1833 25.5
1834 25.5
1835 25.5
1836 25.5
1837 25.5
1838 25.5
1839 25.5
1840 25.5
1841 25.5
1842 25.5
1843 25.5
1844 25.5
1845 25.5
1846 25.5
1847 25.5
1848 25.5
1849 25.5
1850 25.5
1851 25.5
1852 25.5
1853 25.5
1854 25.5
1855 25.5
1856 25.5
1857 25.5
1858 25.5
1859 25.5
1860 25.5
1861 25.5
1862 25.5
1863 25.5
1864 25
1865 24
1866 25.2
1867 25.5
1868 25.5
1869 25.5
1870 25.5
1871 25.48
1872 25.46
1873 25.44
1874 25.42
1875 25.4
1876 25.38
1877 25.14
1878 24.89
1879 24.64
1880 24.39
1881 24.15
1882 23.9
1883 23.65
1884 23.41
1885 23.16
1886 22.92
1887 22.78
1888 22.65
1889 22.51
1890 22.38
1891 21.26
1892 20.65
1893 21.97
1894 21.78
1895 21.58
1896 19.61
1897 18.61
1898 21.4
1899 21.34
1900 21.27
1901 21.22
1902 21.15
1903 21.1
1904 21.03
1905 20.98
1906 20.91
1907 21.06
1908 21.21
1909 21.36
1910 21.51
1911 21.66
1912 21.8
1913 21.95
1914 22.1
1915 22.24
1916 22.39
1917 22.54
1918 12.58
1919 22.83
1920 22.97
1921 23.12
1922 23.26
1923 23.41
1924 23.55
1925 23.7
1926 23.84
1927 24.54
1928 25.24
1929 25.93
1930 26.62
1931 27.32
1932 28.01
1933 28.69
1934 29.38
1935 30.07
1936 30.76
1937 31.44
1938 32.12
1939 32.81
1940 33.49
1941 34.17
1942 31.96
1943 22.25
1944 24.53
1945 34.97
1946 40.52
1947 34.92
1948 36.29
1949 39.48
1950 40.28
1951 40.4
1952 40.68
1953 40.99
1954 41.32
1955 41.67
1956 42.05
1957 42.45
1958 42.88
1959 43.34
1960 43.83
1961 44.33
1962 44.85
1963 45.34
1964 45.79
1965 46.07
1966 46.11
1967 45.87
1968 45.37
1969 44.68
1970 43.97
1971 44.35
1972 52.07
1973 52.09
1974 51.45
1975 52.41
1976 52.61
1977 52.84
1978 53.13
1979 53.49
1980 53.82
1981 54.11
1982 54.39
1983 54.79
1984 55.27
1985 55.26
1986 56.23
1987 56.74
1988 57.1
1989 57.97
1990 58.11
1991 56.47
1992 59.75
1993 60.53
1994 61.29
1995 61.73
1996 62.62
1997 63.5
1998 64.34
1999 65.16
2000 65.48
2001 66.02
2002 66.52
2003 67.07
2004 67.64
2005 68.04
2006 68.5
2007 68.91
2008 69.55
2009 70.07
2010 70.39
2011 70.98
2012 71.25
2013 71.63
2014 72.03
2015 72.41
2016 72.78
2017 73.1
2018 73.41