Year Number 1950 83.875 1951 84.802 1952 85.361 1953 85.506 1954 85.293 1955 84.824 1956 85.536 1957 85.912 1958 86.057 1959 86.018 1960 85.778 1961 86.523 1962 86.945 1963 87.147 1964 87.339 1965 87.757 1966 88.682 1967 89.408 1968 90.052 1969 90.57 1970 90.822 1971 91.964 1972 92.931 1973 93.67 1974 94.172 1975 94.459 1976 95.504 1977 96.226 1978 96.697 1979 97.032 1980 97.342 1981 97.99 1982 98.338 1983 98.474 1984 98.411 1985 98.119 1986 98.399 1987 98.41 1988 98.153 1989 97.627 1990 96.846 1991 96.986 1992 96.784 1993 96.305 1994 95.641 1995 94.849 1996 93.903 1997 92.854 1998 91.728 1999 90.549 2000 89.358 2001 88.523 2002 87.661 2003 86.799 2004 85.969 2005 85.198 2006 84.975 2007 84.683 2008 84.356 2009 84.013 2010 83.648 2011 83.508 2012 83.263 2013 82.908 2014 82.431 2015 81.831 2016 81.295 2017 80.648 2018 79.884 2019 79.002 2020 78.016 2021 77.179 2022 76.221 2023 75.188 2024 74.136 2025 73.104 2026 72.253 2027 71.402 2028 70.558 2029 69.718 2030 68.889 2031 68.247 2032 67.589 2033 66.932 2034 66.295 2035 65.69 2036 65.246 2037 64.801 2038 64.359 2039 63.921 2040 63.486 2041 63.17 2042 62.832 2043 62.477 2044 62.111 2045 61.739 2046 61.447 2047 61.131 2048 60.794 2049 60.441 2050 60.076 2051 59.78 2052 59.46 2053 59.118 2054 58.758 2055 58.385 2056 58.078 2057 57.747 2058 57.401 2059 57.05 2060 56.702 2061 56.422 2062 56.134 2063 55.848 2064 55.574 2065 55.322 2066 55.16 2067 54.999 2068 54.846 2069 54.706 2070 54.585 2071 54.536 2072 54.49 2073 54.444 2074 54.396 2075 54.343 2076 54.335 2077 54.308 2078 54.269 2079 54.227 2080 54.187 2081 54.179 2082 54.162 2083 54.141 2084 54.115 2085 54.086 2086 54.089 2087 54.077 2088 54.059 2089 54.046 2090 54.046 2091 54.074 2092 54.104 2093 54.139 2094 54.181 2095 54.232 2096 54.312 2097 54.392 2098 54.475 2099 54.567 2100 54.673