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 30.41
1872 30.43
1873 30.44
1874 30.46
1875 30.47
1876 30.49
1877 30.5
1878 30.52
1879 30.53
1880 30.55
1881 30.56
1882 30.57
1883 30.59
1884 30.6
1885 30.62
1886 30.63
1887 30.65
1888 30.66
1889 30.68
1890 30.69
1891 30.71
1892 30.72
1893 30.73
1894 30.75
1895 30.76
1896 30.78
1897 30.79
1898 30.81
1899 30.82
1900 30.84
1901 30.85
1902 30.87
1903 30.88
1904 30.89
1905 30.91
1906 30.92
1907 30.94
1908 30.95
1909 30.97
1910 30.98
1911 31
1912 31.01
1913 31.02
1914 31.04
1915 31.05
1916 31.07
1917 31.08
1918 19.93
1919 31.11
1920 31.13
1921 31.14
1922 31.16
1923 31.17
1924 31.18
1925 31.2
1926 31.21
1927 31.23
1928 31.24
1929 31.26
1930 31.27
1931 32.74
1932 34.22
1933 35.68
1934 37.16
1935 38.63
1936 40.12
1937 41.59
1938 41.61
1939 41.63
1940 40.62
1941 39.6
1942 39.62
1943 39.64
1944 39.45
1945 40.74
1946 42.04
1947 43.34
1948 51.76
1949 52.28
1950 52.81
1951 53
1952 53.38
1953 53.8
1954 54.25
1955 54.75
1956 55.28
1957 55.84
1958 56.43
1959 57.03
1960 57.62
1961 58.2
1962 58.73
1963 59.24
1964 59.7
1965 60.13
1966 60.55
1967 60.96
1968 61.4
1969 61.87
1970 62.37
1971 62.84
1972 63.29
1973 63.82
1974 64.38
1975 64.98
1976 65.45
1977 65.75
1978 66.07
1979 66.22
1980 66.37
1981 66.6
1982 66.84
1983 67.32
1984 68.02
1985 68.81
1986 69.37
1987 69.77
1988 70.1
1989 70.38
1990 70.64
1991 70.75
1992 70.72
1993 70.78
1994 70.81
1995 70.91
1996 71.06
1997 71.18
1998 71.34
1999 71.58
2000 71.97
2001 72.4
2002 72.83
2003 73.29
2004 73.39
2005 74.16
2006 74.64
2007 75.1
2008 75.6
2009 76.09
2010 76.57
2011 76.89
2012 77.17
2013 77.32
2014 77.49
2015 77.62
2016 77.75
2017 77.95
2018 78.15