| Year | Value | | 2021 | 83.851219512195 | | 2020 | 83 | | 2019 | 83.904878048781 | | 2018 | 83.753658536585 | | 2017 | 83.551219512195 | | 2016 | 83.60243902439 | | 2015 | 82.89756097561 | | 2014 | 83.19756097561 | | 2013 | 82.79756097561 | | 2012 | 82.69756097561 | | 2011 | 82.69512195122 | | 2010 | 82.246341463415 | | 2009 | 82.043902439024 | | 2008 | 81.992682926829 | | 2007 | 81.741463414634 | | 2006 | 81.490243902439 | | 2005 | 81.236585365854 | | 2004 | 81.087804878049 | | 2003 | 80.536585365854 | | 2002 | 80.385365853658 | | 2001 | 80.180487804878 | | 2000 | 79.680487804878 | | 1999 | 79.580487804878 | | 1998 | 79.324390243902 | | 1997 | 79.079512195122 | | 1996 | 78.896097560976 | | 1995 | 78.417073170732 | | 1994 | 78.35 | | 1993 | 78.085365853659 | | 1992 | 77.806097560976 | | 1991 | 77.514634146342 | | 1990 | 77.24243902439 | | 1989 | 77.421219512195 | | 1988 | 77.226585365854 | | 1987 | 77.19756097561 | | 1986 | 76.899024390244 | | 1985 | 76.733658536585 | | 1984 | 76.608536585366 | | 1983 | 76.031219512195 | | 1982 | 76.033902439024 | | 1981 | 75.693170731707 | | 1980 | 75.459268292683 | | 1979 | 75.466097560976 | | 1978 | 75.187317073171 | | 1977 | 75.238048780488 | | 1976 | 74.785365853659 | | 1975 | 74.665609756098 | | 1974 | 74.287073170732 | | 1973 | 73.940975609756 | | 1972 | 73.644390243902 | | 1971 | 73.130731707317 | | 1970 | 73.020243902439 | | 1969 | 72.612682926829 | | 1968 | 72.590243902439 | | 1967 | 72.636585365854 | | 1966 | 72.335609756098 | | 1965 | 72.201707317073 | | 1964 | 72.077804878049 | | 1963 | 71.18756097561 | | 1962 | 71.196097560976 | | 1961 | 71.64487804878 | | 1960 | 71.313414634146 |
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