Year Number 1950 69.175 1951 68.597 1952 65.69 1953 62.881 1954 61.454 1955 61.643 1956 62.538 1957 64.636 1958 67.379 1959 70.044 1960 72.227 1961 74.42 1962 76.281 1963 77.707 1964 78.633 1965 78.978 1966 79.303 1967 78.886 1968 77.89 1969 76.628 1970 75.3 1971 73.422 1972 71.931 1973 70.626 1974 69.188 1975 67.505 1976 66.557 1977 65.353 1978 64.129 1979 63.185 1980 62.592 1981 61.774 1982 61.262 1983 60.995 1984 60.797 1985 60.559 1986 60.285 1987 60.043 1988 59.854 1989 59.713 1990 59.545 1991 59.87 1992 59.907 1993 59.683 1994 59.224 1995 58.54 1996 57.414 1997 56.152 1998 54.849 1999 53.627 2000 52.588 2001 51.402 2002 50.471 2003 49.626 2004 48.713 2005 47.702 2006 47.035 2007 46.272 2008 45.534 2009 45.023 2010 44.884 2011 45.621 2012 46.557 2013 47.687 2014 48.949 2015 50.27 2016 51.777 2017 53.291 2018 54.696 2019 55.872 2020 56.751 2021 57.1 2022 57.332 2023 57.362 2024 57.132 2025 56.663 2026 56.363 2027 55.782 2028 55.01 2029 54.188 2030 53.389 2031 52.681 2032 52.011 2033 51.421 2034 50.918 2035 50.514 2036 50.34 2037 50.257 2038 50.251 2039 50.303 2040 50.401 2041 50.661 2042 50.942 2043 51.245 2044 51.563 2045 51.886 2046 52.321 2047 52.715 2048 53.103 2049 53.54 2050 54.054 2051 54.738 2052 55.453 2053 56.133 2054 56.689 2055 57.058 2056 57.351 2057 57.485 2058 57.434 2059 57.169 2060 56.694 2061 56.13 2062 55.397 2063 54.553 2064 53.669 2065 52.796 2066 52.051 2067 51.32 2068 50.668 2069 50.174 2070 49.887 2071 49.916 2072 50.119 2073 50.484 2074 50.993 2075 51.629 2076 52.508 2077 53.498 2078 54.542 2079 55.55 2080 56.451 2081 57.32 2082 58.076 2083 58.724 2084 59.279 2085 59.754 2086 60.182 2087 60.528 2088 60.792 2089 60.979 2090 61.098 2091 61.148 2092 61.138 2093 61.086 2094 61.017 2095 60.951 2096 60.878 2097 60.805 2098 60.751 2099 60.737 2100 60.777