Year Number 1950 68.433 1951 69.282 1952 70.345 1953 71.22 1954 71.791 1955 72.15 1956 73.571 1957 74.433 1958 75.069 1959 75.753 1960 76.56 1961 77.573 1962 78.735 1963 79.827 1964 80.515 1965 80.66 1966 81.095 1967 80.945 1968 80.398 1969 79.735 1970 79.108 1971 78.924 1972 78.661 1973 78.311 1974 77.825 1975 77.189 1976 77.038 1977 76.664 1978 76.148 1979 75.594 1980 75.058 1981 74.931 1982 74.783 1983 74.581 1984 74.259 1985 73.791 1986 73.745 1987 73.432 1988 72.933 1989 72.346 1990 71.711 1991 71.293 1992 70.795 1993 70.2 1994 69.477 1995 68.623 1996 67.936 1997 67.135 1998 66.241 1999 65.29 2000 64.31 2001 63.575 2002 62.772 2003 61.922 2004 61.048 2005 60.161 2006 59.443 2007 58.695 2008 57.923 2009 57.115 2010 56.269 2011 55.533 2012 54.734 2013 53.916 2014 53.142 2015 52.449 2016 51.864 2017 51.382 2018 50.957 2019 50.526 2020 50.068 2021 49.779 2022 49.418 2023 49.034 2024 48.694 2025 48.427 2026 48.256 2027 48.14 2028 48.057 2029 47.965 2030 47.844 2031 47.777 2032 47.677 2033 47.555 2034 47.43 2035 47.317 2036 47.274 2037 47.23 2038 47.189 2039 47.153 2040 47.129 2041 47.171 2042 47.22 2043 47.287 2044 47.386 2045 47.527 2046 47.767 2047 48.032 2048 48.324 2049 48.641 2050 48.983 2051 49.39 2052 49.812 2053 50.247 2054 50.689 2055 51.134 2056 51.607 2057 52.073 2058 52.538 2059 53.009 2060 53.492 2061 53.994 2062 54.498 2063 55.008 2064 55.526 2065 56.052 2066 56.595 2067 57.141 2068 57.689 2069 58.242 2070 58.8 2071 59.353 2072 59.909 2073 60.462 2074 61 2075 61.515 2076 61.987 2077 62.437 2078 62.88 2079 63.334 2080 63.811 2081 64.278 2082 64.772 2083 65.291 2084 65.823 2085 66.366 2086 66.874 2087 67.4 2088 67.945 2089 68.505 2090 69.076 2091 69.58 2092 70.104 2093 70.646 2094 71.198 2095 71.756 2096 72.204 2097 72.672 2098 73.157 2099 73.651 2100 74.148