Year Number 1950 89.03 1951 88.667 1952 87.317 1953 85.702 1954 84.133 1955 82.601 1956 82.055 1957 81.643 1958 81.139 1959 80.368 1960 79.323 1961 80.066 1962 80.087 1963 79.752 1964 79.529 1965 79.608 1966 80.926 1967 82.302 1968 83.619 1969 84.617 1970 85.179 1971 86.677 1972 87.515 1973 87.881 1974 88.024 1975 88.069 1976 88.791 1977 89.273 1978 89.509 1979 89.459 1980 89.153 1981 89.538 1982 89.471 1983 89.104 1984 88.586 1985 87.945 1986 88.299 1987 88.728 1988 89.082 1989 89.1 1990 88.585 1991 89.367 1992 89.586 1993 89.409 1994 89.331 1995 89.91 1996 90.46 1997 90.925 1998 91.429 1999 91.793 2000 91.816 2001 92.162 2002 92.049 2003 91.588 2004 90.992 2005 90.422 2006 90.104 2007 89.687 2008 89.168 2009 88.505 2010 87.7 2011 87.2 2012 86.502 2013 85.663 2014 84.72 2015 83.656 2016 82.968 2017 82.246 2018 81.459 2019 80.59 2020 79.659 2021 79.035 2022 78.311 2023 77.518 2024 76.687 2025 75.83 2026 75.173 2027 74.462 2028 73.701 2029 72.892 2030 72.043 2031 71.357 2032 70.607 2033 69.806 2034 68.971 2035 68.112 2036 67.398 2037 66.641 2038 65.856 2039 65.058 2040 64.259 2041 63.607 2042 62.933 2043 62.246 2044 61.556 2045 60.87 2046 60.314 2047 59.743 2048 59.17 2049 58.61 2050 58.071 2051 57.671 2052 57.265 2053 56.858 2054 56.454 2055 56.056 2056 55.766 2057 55.458 2058 55.141 2059 54.82 2060 54.501 2061 54.274 2062 54.032 2063 53.776 2064 53.506 2065 53.226 2066 53.026 2067 52.8 2068 52.559 2069 52.315 2070 52.078 2071 51.93 2072 51.769 2073 51.6 2074 51.427 2075 51.256 2076 51.17 2077 51.066 2078 50.951 2079 50.836 2080 50.724 2081 50.702 2082 50.665 2083 50.617 2084 50.562 2085 50.504 2086 50.53 2087 50.535 2088 50.524 2089 50.501 2090 50.469 2091 50.524 2092 50.55 2093 50.556 2094 50.549 2095 50.536 2096 50.603 2097 50.648 2098 50.68 2099 50.703 2100 50.721