Year Years
1800 33.1
1801 33.1
1802 33.1
1803 33.1
1804 33.1
1805 33.1
1806 33.1
1807 33.1
1808 33.1
1809 33.1
1810 33.1
1811 33.1
1812 33.1
1813 33.1
1814 33.1
1815 33.1
1816 33.1
1817 33.1
1818 33.1
1819 33.1
1820 33.1
1821 33.1
1822 33.1
1823 33.1
1824 33.1
1825 33.1
1826 33.1
1827 33.1
1828 33.1
1829 33.1
1830 33.1
1831 33.1
1832 33.1
1833 33.1
1834 33.1
1835 33.1
1836 33.1
1837 33.1
1838 33.1
1839 33.1
1840 33.1
1841 33.1
1842 33.1
1843 33.1
1844 33.1
1845 33.1
1846 33.1
1847 33.1
1848 33.1
1849 33.1
1850 33.1
1851 33.1
1852 33.1
1853 33.1
1854 33.1
1855 33.1
1856 33.1
1857 33.1
1858 33.1
1859 33.1
1860 33.1
1861 33.1
1862 33.1
1863 33.1
1864 33.1
1865 33.1
1866 33.1
1867 33.1
1868 33.1
1869 33.1
1870 33.1
1871 33.16
1872 33.22
1873 33.28
1874 33.34
1875 33.4
1876 33.46
1877 33.52
1878 33.57
1879 33.63
1880 33.69
1881 33.75
1882 33.81
1883 33.87
1884 33.93
1885 33.99
1886 34.05
1887 34.11
1888 34.17
1889 34.23
1890 34.29
1891 34.35
1892 34.41
1893 34.46
1894 34.52
1895 34.58
1896 34.64
1897 34.7
1898 34.76
1899 34.82
1900 34.88
1901 34.94
1902 35
1903 35.06
1904 35.12
1905 35.18
1906 35.24
1907 35.3
1908 35.35
1909 35.41
1910 35.47
1911 35.53
1912 35.59
1913 35.65
1914 35.71
1915 35.77
1916 35.83
1917 35.89
1918 27.51
1919 36.01
1920 36.07
1921 36.13
1922 36.19
1923 36.24
1924 36.3
1925 36.36
1926 36.42
1927 36.48
1928 36.54
1929 36.6
1930 36.66
1931 36.72
1932 36.78
1933 36.84
1934 36.9
1935 36.96
1936 37.02
1937 37.08
1938 37.13
1939 37.19
1940 36.92
1941 34.95
1942 33.98
1943 33.93
1944 34.21
1945 36.87
1946 38.63
1947 39.63
1948 40.62
1949 41.61
1950 42.61
1951 42.35
1952 41.91
1953 41.79
1954 42.01
1955 42.53
1956 43.4
1957 44.55
1958 45.99
1959 47.64
1960 49.48
1961 51.42
1962 53.39
1963 55.32
1964 57.15
1965 58.87
1966 60.46
1967 61.96
1968 63.39
1969 64.77
1970 66.1
1971 66.91
1972 67.54
1973 68.09
1974 68.55
1975 69.08
1976 69.66
1977 69.69
1978 70.58
1979 71.03
1980 71.45
1981 71.66
1982 71.96
1983 72.21
1984 72.34
1985 72.61
1986 72.74
1987 69.89
1988 72.87
1989 72.93
1990 73.14
1991 73.38
1992 73.48
1993 73.78
1994 73.99
1995 74.12
1996 74.14
1997 74.37
1998 74.41
1999 74.45
2000 74.4
2001 74.62
2002 74.68
2003 74.85
2004 75
2005 75.22
2006 75.44
2007 75.56
2008 75.73
2009 75.89
2010 76.1
2011 60.95
2012 75.55
2013 75.95
2014 74.44
2015 74.16
2016 75.11
2017 75.29
2018 75.47