Year Number 1950 83.094 1951 82.456 1952 81.415 1953 80.292 1954 79.268 1955 78.394 1956 78.437 1957 78.492 1958 78.55 1959 78.622 1960 78.759 1961 79.727 1962 80.375 1963 80.896 1964 81.478 1965 82.204 1966 83.513 1967 84.656 1968 85.662 1969 86.511 1970 87.222 1971 88.356 1972 89.121 1973 89.612 1974 89.929 1975 90.151 1976 91.102 1977 91.758 1978 92.159 1979 92.31 1980 92.238 1981 92.802 1982 92.921 1983 92.715 1984 92.303 1985 91.759 1986 91.86 1987 91.773 1988 91.49 1989 90.994 1990 90.312 1991 89.961 1992 89.36 1993 88.591 1994 87.757 1995 86.927 1996 86.961 1997 86.925 1998 86.8 1999 86.547 2000 86.154 2001 86.958 2002 87.569 2003 88.001 2004 88.3 2005 88.496 2006 88.534 2007 88.452 2008 88.231 2009 87.863 2010 87.377 2011 86.742 2012 86.02 2013 85.22 2014 84.365 2015 83.49 2016 83.034 2017 82.469 2018 81.847 2019 81.232 2020 80.654 2021 80.319 2022 79.969 2023 79.579 2024 79.115 2025 78.569 2026 78.141 2027 77.622 2028 77.017 2029 76.342 2030 75.62 2031 75.034 2032 74.383 2033 73.681 2034 72.948 2035 72.204 2036 71.621 2037 71.007 2038 70.373 2039 69.727 2040 69.082 2041 68.595 2042 68.081 2043 67.547 2044 66.996 2045 66.437 2046 65.99 2047 65.517 2048 65.024 2049 64.52 2050 64.014 2051 63.617 2052 63.204 2053 62.781 2054 62.356 2055 61.938 2056 61.638 2057 61.322 2058 60.999 2059 60.682 2060 60.377 2061 60.171 2062 59.957 2063 59.732 2064 59.497 2065 59.25 2066 59.065 2067 58.861 2068 58.639 2069 58.399 2070 58.143 2071 57.951 2072 57.73 2073 57.495 2074 57.264 2075 57.047 2076 56.901 2077 56.759 2078 56.621 2079 56.486 2080 56.354 2081 56.285 2082 56.205 2083 56.12 2084 56.04 2085 55.97 2086 55.94 2087 55.912 2088 55.885 2089 55.856 2090 55.826 2091 55.827 2092 55.816 2093 55.8 2094 55.785 2095 55.778 2096 55.791 2097 55.802 2098 55.814 2099 55.829 2100 55.847