Year Years
1800 28.75
1801 28.75
1802 28.75
1803 28.75
1804 28.75
1805 28.75
1806 28.75
1807 28.75
1808 28.75
1809 28.75
1810 28.75
1811 28.75
1812 28.75
1813 28.75
1814 28.75
1815 28.75
1816 28.75
1817 28.75
1818 28.75
1819 28.75
1820 28.75
1821 28.75
1822 28.75
1823 28.75
1824 28.75
1825 28.75
1826 28.75
1827 28.75
1828 28.75
1829 28.75
1830 28.75
1831 28.75
1832 28.75
1833 28.75
1834 28.75
1835 28.75
1836 28.75
1837 28.75
1838 28.75
1839 28.75
1840 28.75
1841 28.75
1842 28.75
1843 28.75
1844 28.75
1845 28.75
1846 28.75
1847 28.75
1848 28.75
1849 28.75
1850 28.75
1851 28.75
1852 28.75
1853 28.75
1854 28.75
1855 28.75
1856 28.75
1857 28.75
1858 28.75
1859 28.75
1860 28.75
1861 28.75
1862 28.75
1863 28.75
1864 28.75
1865 28.75
1866 28.75
1867 28.75
1868 28.75
1869 28.75
1870 28.75
1871 28.79
1872 28.82
1873 28.86
1874 28.89
1875 28.93
1876 28.96
1877 29
1878 29.03
1879 29.07
1880 29.1
1881 29.14
1882 29.17
1883 29.21
1884 29.24
1885 29.28
1886 29.31
1887 29.35
1888 29.38
1889 29.42
1890 29.45
1891 29.49
1892 29.52
1893 29.56
1894 29.59
1895 29.63
1896 29.66
1897 29.7
1898 29.73
1899 29.77
1900 29.8
1901 29.84
1902 29.87
1903 29.91
1904 29.94
1905 29.98
1906 30.01
1907 30.05
1908 30.08
1909 30.12
1910 30.15
1911 30.19
1912 30.22
1913 30.26
1914 30.29
1915 30.33
1916 30.36
1917 30.4
1918 5.99
1919 30.47
1920 30.5
1921 30.54
1922 30.57
1923 30.61
1924 30.64
1925 30.68
1926 30.71
1927 30.75
1928 30.78
1929 30.82
1930 30.85
1931 30.89
1932 30.92
1933 30.96
1934 30.99
1935 31.03
1936 31.06
1937 31.1
1938 31.13
1939 31.17
1940 31.2
1941 31.24
1942 31.27
1943 31.31
1944 31.34
1945 31.38
1946 33.4
1947 35.44
1948 37.47
1949 39.52
1950 41.56
1951 41.78
1952 42.19
1953 42.61
1954 43.07
1955 43.52
1956 44.01
1957 44.51
1958 45.03
1959 45.57
1960 46.1
1961 46.64
1962 47.18
1963 47.72
1964 48.26
1965 48.8
1966 49.34
1967 49.91
1968 50.49
1969 51.1
1970 51.71
1971 52.03
1972 52.47
1973 52.84
1974 53.22
1975 53.64
1976 53.95
1977 54.32
1978 54.79
1979 55.24
1980 55.6
1981 56
1982 56.48
1983 56.93
1984 57.23
1985 57.82
1986 57.92
1987 58.4
1988 58.55
1989 58.55
1990 58.45
1991 58.16
1992 57.86
1993 57.35
1994 56.97
1995 56.49
1996 56.06
1997 55.51
1998 55
1999 54.78
2000 54.46
2001 54.43
2002 54.45
2003 54.52
2004 54.64
2005 54.87
2006 55.28
2007 55.61
2008 56.18
2009 56.77
2010 57.25
2011 57.68
2012 58.26
2013 58.75
2014 59.16
2015 59.66
2016 60.18
2017 60.7
2018 61.22