Year Years
1800 25.6
1801 25.6
1802 25.6
1803 25.6
1804 25.6
1805 25.6
1806 25.6
1807 25.6
1808 25.6
1809 25.6
1810 25.6
1811 25.6
1812 25.6
1813 25.6
1814 25.6
1815 25.6
1816 25.6
1817 25.6
1818 25.6
1819 25.6
1820 25.6
1821 25.6
1822 25.6
1823 25.6
1824 25.6
1825 25.6
1826 25.6
1827 25.6
1828 25.6
1829 25.6
1830 25.6
1831 25.6
1832 25.6
1833 25.6
1834 25.6
1835 25.6
1836 25.6
1837 25.6
1838 25.6
1839 25.6
1840 25.6
1841 20
1842 25.6
1843 25.6
1844 25.6
1845 25.6
1846 25.6
1847 25.6
1848 25.6
1849 25.6
1850 25.6
1851 25.6
1852 25.6
1853 25.6
1854 6
1855 25.6
1856 25.6
1857 25.6
1858 25.6
1859 25.6
1860 25.6
1861 25.6
1862 25.6
1863 25.6
1864 25.6
1865 25.6
1866 25.6
1867 25.6
1868 25.6
1869 25.6
1870 25.6
1871 25.6
1872 25.6
1873 25.6
1874 25.6
1875 25.6
1876 25.6
1877 25.6
1878 25.6
1879 25.6
1880 25.6
1881 25.6
1882 25.6
1883 25.6
1884 25.6
1885 25.6
1886 25.6
1887 25.6
1888 25.6
1889 25.6
1890 25.6
1891 25.6
1892 25.6
1893 25.6
1894 25.6
1895 25.6
1896 25.6
1897 25.6
1898 25.6
1899 25.6
1900 25.6
1901 25.6
1902 25.6
1903 25.6
1904 25.6
1905 25.6
1906 25.6
1907 25.6
1908 25.6
1909 25.6
1910 25.6
1911 25.6
1912 25.6
1913 25.6
1914 25.6
1915 25.6
1916 25.6
1917 25.6
1918 1
1919 25.6
1920 25.6
1921 25.6
1922 25.6
1923 25.6
1924 25.6
1925 25.6
1926 26.4
1927 27.2
1928 28
1929 28.8
1930 29.6
1931 30.4
1932 31.2
1933 32
1934 32.8
1935 33.6
1936 34.4
1937 35.2
1938 36
1939 36.8
1940 37.6
1941 38.4
1942 39.2
1943 40
1944 40.8
1945 41.6
1946 42.4
1947 43.2
1948 44
1949 44.8
1950 45.6
1951 46.52
1952 48.28
1953 49.86
1954 51.27
1955 52.5
1956 53.55
1957 54.44
1958 55.18
1959 55.78
1960 56.28
1961 56.71
1962 57.09
1963 57.47
1964 57.85
1965 58.24
1966 58.65
1967 59.06
1968 59.45
1969 59.83
1970 60.18
1971 60.52
1972 60.84
1973 61.15
1974 61.47
1975 61.82
1976 62.23
1977 62.72
1978 63.28
1979 63.9
1980 64.56
1981 65.22
1982 65.84
1983 66.39
1984 66.87
1985 67.27
1986 67.59
1987 67.88
1988 68.15
1989 68.42
1990 68.7
1991 69.01
1992 69.33
1993 69.68
1994 70.05
1995 70.43
1996 70.82
1997 71.21
1998 71.59
1999 71.96
2000 72.31
2001 72.67
2002 73.03
2003 73.4
2004 73.77
2005 74.13
2006 74.48
2007 74.81
2008 75.11
2009 75.38
2010 75.62
2011 75.84
2012 76.05
2013 76.26
2014 76.47
2015 76.69
2016 76.88
2017 77.06
2018 77.24