Year Number 1950 91.596 1951 91.429 1952 91.057 1953 90.822 1954 90.64 1955 90.363 1956 90.935 1957 91.458 1958 91.885 1959 92.272 1960 92.696 1961 93.693 1962 94.681 1963 95.578 1964 96.23 1965 96.544 1966 97.276 1967 97.37 1968 97.016 1969 96.42 1970 95.642 1971 94.501 1972 93.283 1973 91.909 1974 90.296 1975 88.47 1976 86.548 1977 84.663 1978 82.805 1979 80.981 1980 79.221 1981 78.009 1982 76.652 1983 75.323 1984 74.223 1985 73.418 1986 72.76 1987 72.386 1988 72.143 1989 71.796 1990 71.228 1991 70.782 1992 70.045 1993 69.123 1994 68.17 1995 67.252 1996 66.288 1997 65.403 1998 64.533 1999 63.59 2000 62.551 2001 61.579 2002 60.55 2003 59.505 2004 58.508 2005 57.591 2006 56.823 2007 56.095 2008 55.423 2009 54.813 2010 54.264 2011 53.799 2012 53.394 2013 53.035 2014 52.699 2015 52.375 2016 52.097 2017 51.823 2018 51.563 2019 51.329 2020 51.129 2021 50.964 2022 50.822 2023 50.713 2024 50.651 2025 50.646 2026 50.7 2027 50.799 2028 50.925 2029 51.057 2030 51.183 2031 51.305 2032 51.421 2033 51.525 2034 51.612 2035 51.678 2036 51.713 2037 51.725 2038 51.736 2039 51.777 2040 51.865 2041 51.979 2042 52.133 2043 52.325 2044 52.547 2045 52.797 2046 53.047 2047 53.319 2048 53.623 2049 53.973 2050 54.377 2051 54.794 2052 55.255 2053 55.749 2054 56.256 2055 56.76 2056 57.213 2057 57.667 2058 58.121 2059 58.575 2060 59.034 2061 59.439 2062 59.848 2063 60.268 2064 60.71 2065 61.183 2066 61.599 2067 62.039 2068 62.512 2069 63.023 2070 63.567 2071 64.03 2072 64.531 2073 65.065 2074 65.629 2075 66.223 2076 66.724 2077 67.253 2078 67.816 2079 68.41 2080 69.027 2081 69.523 2082 70.052 2083 70.605 2084 71.176 2085 71.764 2086 72.211 2087 72.681 2088 73.177 2089 73.698 2090 74.244 2091 74.629 2092 75.042 2093 75.484 2094 75.958 2095 76.461 2096 76.782 2097 77.145 2098 77.553 2099 77.997 2100 78.467