Year Number 1950 69.63 1951 71.109 1952 72.91 1953 74.286 1954 74.972 1955 75.063 1956 76.463 1957 76.836 1958 76.681 1959 76.461 1960 76.344 1961 76.735 1962 77.318 1963 77.862 1964 78 1965 77.62 1966 77.913 1967 77.621 1968 77.005 1969 76.423 1970 76.042 1971 76.611 1972 77.207 1973 77.823 1974 78.388 1975 78.861 1976 80.141 1977 81.224 1978 82.171 1979 83.072 1980 83.985 1981 85.542 1982 87.047 1983 88.443 1984 89.61 1985 90.477 1986 92.059 1987 93.039 1988 93.584 1989 93.906 1990 94.099 1991 94.602 1992 94.946 1993 95.048 1994 94.751 1995 94.006 1996 93.719 1997 92.904 1998 91.732 1999 90.418 2000 89.08 2001 88.25 2002 87.324 2003 86.33 2004 85.27 2005 84.159 2006 83.615 2007 82.936 2008 82.171 2009 81.382 2010 80.61 2011 80.305 2012 79.909 2013 79.461 2014 78.974 2015 78.448 2016 78.351 2017 78.089 2018 77.683 2019 77.153 2020 76.51 2021 76.054 2022 75.459 2023 74.735 2024 73.881 2025 72.912 2026 72.164 2027 71.277 2028 70.292 2029 69.26 2030 68.215 2031 67.443 2032 66.618 2033 65.768 2034 64.911 2035 64.06 2036 63.481 2037 62.866 2038 62.234 2039 61.601 2040 60.975 2041 60.574 2042 60.141 2043 59.695 2044 59.247 2045 58.808 2046 58.574 2047 58.304 2048 58.003 2049 57.673 2050 57.317 2051 57.098 2052 56.827 2053 56.514 2054 56.173 2055 55.813 2056 55.585 2057 55.313 2058 55.008 2059 54.675 2060 54.326 2061 54.105 2062 53.844 2063 53.557 2064 53.256 2065 52.953 2066 52.789 2067 52.596 2068 52.387 2069 52.173 2070 51.963 2071 51.89 2072 51.796 2073 51.689 2074 51.579 2075 51.472 2076 51.501 2077 51.505 2078 51.489 2079 51.456 2080 51.408 2081 51.47 2082 51.495 2083 51.49 2084 51.461 2085 51.414 2086 51.464 2087 51.477 2088 51.461 2089 51.422 2090 51.368 2091 51.417 2092 51.428 2093 51.412 2094 51.382 2095 51.347 2096 51.422 2097 51.471 2098 51.502 2099 51.519 2100 51.529