Year Number 1950 84.69 1951 85.4 1952 86.035 1953 86.606 1954 87.125 1955 87.599 1956 88.35 1957 88.981 1958 89.514 1959 89.98 1960 90.39 1961 91.053 1962 91.583 1963 91.99 1964 92.263 1965 92.387 1966 92.638 1967 92.681 1968 92.537 1969 92.237 1970 91.793 1971 91.354 1972 90.78 1973 90.064 1974 89.18 1975 88.124 1976 87.166 1977 85.995 1978 84.686 1979 83.324 1980 81.951 1981 80.563 1982 79.192 1983 77.823 1984 76.429 1985 75.014 1986 73.649 1987 72.298 1988 70.973 1989 69.683 1990 68.438 1991 67.314 1992 66.168 1993 65.052 1994 64.038 1995 63.161 1996 62.334 1997 61.684 1998 61.134 1999 60.565 2000 59.923 2001 59.46 2002 58.824 2003 58.117 2004 57.485 2005 56.989 2006 56.447 2007 56.093 2008 55.835 2009 55.536 2010 55.147 2011 54.869 2012 54.479 2013 54.041 2014 53.656 2015 53.367 2016 53.163 2017 53.014 2018 52.91 2019 52.825 2020 52.747 2021 52.685 2022 52.646 2023 52.624 2024 52.612 2025 52.613 2026 52.669 2027 52.728 2028 52.8 2029 52.902 2030 53.044 2031 53.217 2032 53.42 2033 53.656 2034 53.924 2035 54.225 2036 54.522 2037 54.846 2038 55.193 2039 55.553 2040 55.922 2041 56.25 2042 56.582 2043 56.92 2044 57.267 2045 57.623 2046 57.918 2047 58.218 2048 58.529 2049 58.858 2050 59.21 2051 59.5 2052 59.814 2053 60.15 2054 60.499 2055 60.859 2056 61.126 2057 61.404 2058 61.707 2059 62.056 2060 62.461 2061 62.802 2062 63.203 2063 63.649 2064 64.111 2065 64.569 2066 64.891 2067 65.22 2068 65.566 2069 65.945 2070 66.372 2071 66.693 2072 67.064 2073 67.485 2074 67.952 2075 68.462 2076 68.848 2077 69.285 2078 69.769 2079 70.292 2080 70.843 2081 71.234 2082 71.663 2083 72.126 2084 72.623 2085 73.157 2086 73.515 2087 73.912 2088 74.357 2089 74.848 2090 75.373 2091 75.696 2092 76.073 2093 76.492 2094 76.944 2095 77.433 2096 77.728 2097 78.062 2098 78.439 2099 78.868 2100 79.348