Year Number 1950 58.078 1951 57.438 1952 57.086 1953 56.713 1954 56.245 1955 55.714 1956 55.748 1957 55.463 1958 54.988 1959 54.477 1960 54.045 1961 54.516 1962 54.996 1963 55.589 1964 56.271 1965 56.96 1966 57.495 1967 58.021 1968 58.485 1969 58.865 1970 59.163 1971 58.996 1972 58.8 1973 58.507 1974 58.026 1975 57.335 1976 56.768 1977 55.931 1978 54.946 1979 53.97 1980 53.081 1981 52.13 1982 51.316 1983 50.645 1984 50.099 1985 49.685 1986 49.67 1987 49.721 1988 49.845 1989 50.037 1990 50.25 1991 50.685 1992 51.077 1993 51.388 1994 51.576 1995 51.617 1996 51.645 1997 51.574 1998 51.362 1999 50.972 2000 50.408 2001 50.258 2002 50.05 2003 49.754 2004 49.391 2005 49.009 2006 48.702 2007 48.364 2008 48.039 2009 47.782 2010 47.628 2011 47.969 2012 48.384 2013 48.847 2014 49.382 2015 50.066 2016 50.466 2017 50.911 2018 51.448 2019 52.098 2020 52.841 2021 53.669 2022 54.674 2023 55.764 2024 56.811 2025 57.751 2026 59.057 2027 60.192 2028 61.144 2029 61.922 2030 62.517 2031 63.01 2032 63.321 2033 63.502 2034 63.612 2035 63.691 2036 63.884 2037 64.094 2038 64.256 2039 64.296 2040 64.191 2041 64.129 2042 63.931 2043 63.663 2044 63.401 2045 63.177 2046 63.125 2047 63.098 2048 63.127 2049 63.243 2050 63.469 2051 63.939 2052 64.5 2053 65.165 2054 65.936 2055 66.792 2056 67.863 2057 69.05 2058 70.213 2059 71.16 2060 71.782 2061 72.212 2062 72.321 2063 72.177 2064 71.868 2065 71.442 2066 70.923 2067 70.323 2068 69.664 2069 68.98 2070 68.316 2071 67.731 2072 67.189 2073 66.732 2074 66.417 2075 66.274 2076 66.321 2077 66.543 2078 66.889 2079 67.272 2080 67.626 2081 67.972 2082 68.293 2083 68.622 2084 68.993 2085 69.41 2086 69.883 2087 70.431 2088 70.997 2089 71.514 2090 71.957 2091 72.33 2092 72.65 2093 72.915 2094 73.123 2095 73.269 2096 73.244 2097 73.17 2098 73.056 2099 72.93 2100 72.815