Year Years
1800 30.4
1801 30.4
1802 30.4
1803 30.4
1804 30.4
1805 30.4
1806 30.4
1807 30.4
1808 30.4
1809 30.4
1810 30.4
1811 30.4
1812 30.4
1813 30.4
1814 30.4
1815 30.4
1816 30.4
1817 30.4
1818 30.4
1819 30.4
1820 30.4
1821 30.4
1822 30.4
1823 30.4
1824 30.4
1825 30.4
1826 30.4
1827 30.4
1828 30.4
1829 30.4
1830 30.4
1831 30.4
1832 30.4
1833 30.4
1834 30.4
1835 30.4
1836 30.4
1837 30.4
1838 30.4
1839 30.4
1840 30.4
1841 30.4
1842 30.4
1843 30.4
1844 30.4
1845 30.4
1846 30.4
1847 30.4
1848 30.4
1849 30.4
1850 30.4
1851 30.4
1852 30.4
1853 30.4
1854 30.4
1855 30.4
1856 30.4
1857 30.4
1858 30.4
1859 30.4
1860 30.4
1861 30.4
1862 30.4
1863 30.4
1864 30.4
1865 30.4
1866 30.4
1867 30.4
1868 30.4
1869 30.4
1870 30.4
1871 30.51
1872 30.62
1873 30.72
1874 30.83
1875 30.94
1876 31.05
1877 31.15
1878 31.26
1879 31.37
1880 31.48
1881 31.58
1882 31.69
1883 31.8
1884 31.91
1885 32.01
1886 32.12
1887 32.23
1888 32.34
1889 32.45
1890 32.55
1891 32.66
1892 32.77
1893 32.88
1894 32.98
1895 33.09
1896 33.2
1897 33.31
1898 33.41
1899 33.52
1900 33.63
1901 33.74
1902 33.85
1903 33.95
1904 34.06
1905 34.17
1906 34.28
1907 34.38
1908 34.49
1909 34.6
1910 34.71
1911 34.81
1912 34.92
1913 35.03
1914 35.14
1915 35.24
1916 35.35
1917 35.46
1918 16.8
1919 35.68
1920 35.78
1921 35.89
1922 36
1923 36.11
1924 36.21
1925 36.32
1926 36.43
1927 36.54
1928 36.64
1929 36.75
1930 36.86
1931 36.97
1932 37.08
1933 37.18
1934 37.29
1935 37.4
1936 37.51
1937 37.61
1938 37.72
1939 37.83
1940 37.94
1941 38.04
1942 38.15
1943 38.26
1944 38.37
1945 38.47
1946 39.33
1947 40.18
1948 41.04
1949 41.9
1950 42.77
1951 43.1
1952 43.64
1953 44.21
1954 44.83
1955 45.47
1956 46.14
1957 46.84
1958 47.56
1959 48.29
1960 49.04
1961 49.77
1962 50.5
1963 51.19
1964 51.86
1965 52.51
1966 53.14
1967 45.68
1968 39.07
1969 36.47
1970 50.1
1971 50.49
1972 50.97
1973 51.49
1974 52.1
1975 52.56
1976 53.01
1977 53.54
1978 53.97
1979 54.38
1980 54.65
1981 54.87
1982 55.1
1983 55.27
1984 55.4
1985 55.65
1986 55.46
1987 55.25
1988 55.08
1989 54.94
1990 54.89
1991 54.67
1992 54.67
1993 54.61
1994 54.77
1995 54.72
1996 54.49
1997 54.69
1998 54.64
1999 54.8
2000 54.92
2001 55.15
2002 55.15
2003 55.6
2004 56.14
2005 56.86
2006 57.49
2007 58.22
2008 59.02
2009 59.76
2010 60.53
2011 61.29
2012 61.95
2013 62.52
2014 63
2015 64.05
2016 65.05
2017 65.6
2018 66.14