Year Years
1800 25.8
1801 25.8
1802 25.8
1803 25.8
1804 25.8
1805 25.8
1806 25.8
1807 25.8
1808 25.8
1809 25.8
1810 25.8
1811 25.8
1812 25.8
1813 25.8
1814 25.8
1815 25.8
1816 25.8
1817 25.8
1818 25.8
1819 25.8
1820 25.8
1821 25.8
1822 25.8
1823 25.8
1824 25.8
1825 25.8
1826 25.8
1827 25.8
1828 25.8
1829 25.8
1830 25.8
1831 25.8
1832 25.8
1833 25.8
1834 25.8
1835 25.8
1836 25.8
1837 25.8
1838 25.8
1839 25.8
1840 25.8
1841 25.8
1842 25.8
1843 25.8
1844 25.8
1845 25.8
1846 25.8
1847 25.8
1848 25.8
1849 25.8
1850 25.8
1851 25.8
1852 25.8
1853 25.8
1854 25.8
1855 25.8
1856 25.8
1857 25.8
1858 25.8
1859 25.8
1860 25.8
1861 25.8
1862 25.8
1863 25.8
1864 25.8
1865 25.8
1866 25.8
1867 25.8
1868 25.8
1869 25.8
1870 25.8
1871 25.8
1872 25.81
1873 25.81
1874 25.81
1875 25.82
1876 25.82
1877 25.82
1878 25.83
1879 25.83
1880 25.83
1881 25.84
1882 25.84
1883 25.84
1884 25.85
1885 25.85
1886 25.85
1887 25.86
1888 25.86
1889 25.87
1890 25.87
1891 25.87
1892 25.88
1893 25.88
1894 25.88
1895 25.89
1896 25.89
1897 25.89
1898 25.9
1899 25.9
1900 25.9
1901 25.91
1902 25.91
1903 25.91
1904 25.45
1905 25
1906 24.54
1907 24.09
1908 23.63
1909 23.92
1910 24.23
1911 24.52
1912 24.83
1913 25.12
1914 25.63
1915 26.14
1916 26.64
1917 27.15
1918 17.14
1919 27.67
1920 28.19
1921 28.7
1922 29.22
1923 29.74
1924 30.57
1925 31.39
1926 32.22
1927 33.04
1928 33.87
1929 34.63
1930 35.4
1931 36.16
1932 36.93
1933 37.7
1934 38.75
1935 39.8
1936 40.86
1937 41.9
1938 42.95
1939 43.55
1940 44.14
1941 44.73
1942 45.32
1943 43.42
1944 42.41
1945 42.92
1946 45.45
1947 47.48
1948 48.08
1949 48.54
1950 43.46
1951 40.94
1952 40.44
1953 45.5
1954 48.54
1955 50.09
1956 50.76
1957 51.46
1958 52.17
1959 52.89
1960 53.62
1961 54.37
1962 55.14
1963 55.91
1964 56.7
1965 57.52
1966 58.37
1967 59.25
1968 60.17
1969 61.09
1970 61.98
1971 62.41
1972 62.76
1973 63.28
1974 63.72
1975 64.28
1976 64.93
1977 65.58
1978 66.37
1979 67.04
1980 67.49
1981 68.08
1982 68.47
1983 68.83
1984 69.34
1985 69.79
1986 70.24
1987 70.65
1988 71.19
1989 71.62
1990 72.03
1991 72.48
1992 72.93
1993 73.34
1994 73.74
1995 74.16
1996 74.62
1997 75.04
1998 75.33
1999 75.66
2000 75.98
2001 76.31
2002 76.73
2003 77.25
2004 77.83
2005 78.35
2006 78.8
2007 79.19
2008 79.55
2009 79.87
2010 80.13
2011 80.42
2012 80.64
2013 80.87
2014 80.91
2015 80.94
2016 80.94
2017 81.15
2018 81.35