Year Number 1950 51.08 1951 52.148 1952 52.976 1953 53.865 1954 54.856 1955 55.849 1956 56.411 1957 57.198 1958 57.952 1959 58.456 1960 58.648 1961 58.92 1962 58.784 1963 58.423 1964 58.139 1965 58.087 1966 58.184 1967 58.509 1968 58.97 1969 59.377 1970 59.626 1971 59.989 1972 60.114 1973 60.081 1974 60.002 1975 59.912 1976 59.748 1977 59.542 1978 59.268 1979 58.893 1980 58.416 1981 57.796 1982 57.184 1983 56.573 1984 55.977 1985 55.431 1986 55.164 1987 54.896 1988 54.661 1989 54.495 1990 54.404 1991 54.486 1992 54.589 1993 54.711 1994 54.815 1995 54.865 1996 54.893 1997 54.853 1998 54.742 1999 54.55 2000 54.268 2001 53.95 2002 53.56 2003 53.126 2004 52.707 2005 52.357 2006 51.889 2007 51.53 2008 51.282 2009 51.137 2010 51.091 2011 51.057 2012 51.131 2013 51.377 2014 51.77 2015 52.21 2016 52.772 2017 53.328 2018 53.873 2019 54.4 2020 54.915 2021 55.576 2022 56.207 2023 56.818 2024 57.43 2025 58.051 2026 58.582 2027 59.131 2028 59.704 2029 60.305 2030 60.944 2031 61.54 2032 62.168 2033 62.811 2034 63.456 2035 64.093 2036 64.591 2037 65.085 2038 65.569 2039 65.995 2040 66.322 2041 66.443 2042 66.515 2043 66.551 2044 66.602 2045 66.726 2046 66.841 2047 67.028 2048 67.301 2049 67.65 2050 68.048 2051 68.334 2052 68.693 2053 69.105 2054 69.554 2055 70.04 2056 70.412 2057 70.831 2058 71.281 2059 71.726 2060 72.129 2061 72.31 2062 72.489 2063 72.655 2064 72.794 2065 72.907 2066 72.84 2067 72.787 2068 72.755 2069 72.769 2070 72.858 2071 72.831 2072 72.89 2073 73.036 2074 73.251 2075 73.507 2076 73.556 2077 73.671 2078 73.85 2079 74.095 2080 74.411 2081 74.558 2082 74.796 2083 75.115 2084 75.493 2085 75.909 2086 76.112 2087 76.381 2088 76.702 2089 77.062 2090 77.462 2091 77.641 2092 77.869 2093 78.147 2094 78.475 2095 78.85 2096 78.972 2097 79.147 2098 79.376 2099 79.664 2100 80.009