Year Number 1950 78.4 1951 79.747 1952 80.962 1953 82.289 1954 83.573 1955 84.607 1956 85.534 1957 86.153 1958 86.425 1959 86.446 1960 86.327 1961 86.707 1962 87.229 1963 87.793 1964 88.105 1965 87.921 1966 88.008 1967 87.255 1968 86.032 1969 84.871 1970 84.001 1971 81.222 1972 79.321 1973 77.811 1974 76.061 1975 73.869 1976 72.244 1977 70.058 1978 67.772 1979 66.041 1980 65.12 1981 64.664 1982 64.915 1983 65.579 1984 66.12 1985 66.23 1986 66.861 1987 66.782 1988 66.21 1989 65.521 1990 64.876 1991 63.532 1992 62.488 1993 61.479 1994 60.132 1995 58.309 1996 56.3 1997 54.001 1998 51.565 1999 49.276 2000 47.296 2001 45.503 2002 43.991 2003 42.758 2004 41.769 2005 41.004 2006 40.627 2007 40.424 2008 40.404 2009 40.562 2010 40.874 2011 41.256 2012 41.714 2013 42.225 2014 42.748 2015 43.249 2016 43.769 2017 44.252 2018 44.674 2019 45.034 2020 45.339 2021 45.561 2022 45.722 2023 45.837 2024 45.946 2025 46.082 2026 46.365 2027 46.673 2028 46.958 2029 47.152 2030 47.224 2031 47.309 2032 47.281 2033 47.202 2034 47.154 2035 47.183 2036 47.42 2037 47.72 2038 48.074 2039 48.458 2040 48.864 2041 49.439 2042 50.005 2043 50.615 2044 51.354 2045 52.268 2046 53.491 2047 54.858 2048 56.28 2049 57.631 2050 58.825 2051 60.025 2052 61.056 2053 61.904 2054 62.549 2055 62.975 2056 63.332 2057 63.477 2058 63.43 2059 63.225 2060 62.906 2061 62.639 2062 62.265 2063 61.841 2064 61.437 2065 61.091 2066 60.981 2067 60.925 2068 60.923 2069 60.981 2070 61.105 2071 61.505 2072 61.953 2073 62.451 2074 62.973 2075 63.487 2076 64.197 2077 64.908 2078 65.581 2079 66.17 2080 66.647 2081 67.208 2082 67.668 2083 68.024 2084 68.277 2085 68.43 2086 68.606 2087 68.687 2088 68.683 2089 68.619 2090 68.511 2091 68.451 2092 68.347 2093 68.221 2094 68.095 2095 67.979 2096 67.949 2097 67.936 2098 67.95 2099 67.994 2100 68.062