Year Number 1950 77.469 1951 75.745 1952 74.201 1953 72.7 1954 71.238 1955 69.887 1956 69.949 1957 69.772 1958 69.543 1959 69.428 1960 69.486 1961 69.562 1962 69.883 1963 70.235 1964 70.231 1965 69.626 1966 69.776 1967 69.372 1968 68.542 1969 67.669 1970 67.072 1971 65.623 1972 64.478 1973 63.5 1974 62.409 1975 61.063 1976 60.103 1977 58.834 1978 57.4 1979 56.043 1980 54.892 1981 53.619 1982 52.633 1983 51.849 1984 51.113 1985 50.358 1986 50.512 1987 50.533 1988 50.5 1989 50.566 1990 50.792 1991 50.282 1992 50.047 1993 49.972 1994 49.896 1995 49.748 1996 49.821 1997 49.754 1998 49.578 1999 49.394 2000 49.282 2001 49.394 2002 49.565 2003 49.763 2004 49.868 2005 49.794 2006 49.663 2007 49.411 2008 49.057 2009 48.675 2010 48.316 2011 48.109 2012 47.824 2013 47.578 2014 47.517 2015 47.71 2016 48.103 2017 48.778 2018 49.598 2019 50.338 2020 50.876 2021 51.388 2022 51.689 2023 51.866 2024 52.069 2025 52.386 2026 52.851 2027 53.399 2028 53.988 2029 54.509 2030 54.916 2031 55.284 2032 55.552 2033 55.757 2034 55.963 2035 56.22 2036 56.547 2037 56.908 2038 57.292 2039 57.682 2040 58.071 2041 58.5 2042 58.906 2043 59.325 2044 59.805 2045 60.366 2046 61.066 2047 61.866 2048 62.688 2049 63.415 2050 63.985 2051 64.495 2052 64.854 2053 65.128 2054 65.423 2055 65.791 2056 66.259 2057 66.809 2058 67.411 2059 68.025 2060 68.637 2061 69.269 2062 69.915 2063 70.566 2064 71.2 2065 71.794 2066 72.319 2067 72.807 2068 73.276 2069 73.757 2070 74.275 2071 74.792 2072 75.357 2073 75.951 2074 76.517 2075 77.008 2076 77.381 2077 77.726 2078 78.03 2079 78.292 2080 78.531 2081 78.698 2082 78.861 2083 79.03 2084 79.212 2085 79.395 2086 79.447 2087 79.537 2088 79.653 2089 79.788 2090 79.938 2091 79.98 2092 80.081 2093 80.23 2094 80.412 2095 80.619 2096 80.725 2097 80.878 2098 81.068 2099 81.293 2100 81.552