Year | Value | 2021 | 56.204 | 2020 | 58.111 | 2019 | 58.312 | 2018 | 57.721 | 2017 | 57.213 | 2016 | 56.492 | 2015 | 55.748 | 2014 | 54.989 | 2013 | 54.336 | 2012 | 53.63 | 2011 | 53.03 | 2010 | 52.441 | 2009 | 52.18 | 2008 | 51.529 | 2007 | 51.037 | 2006 | 50.551 | 2005 | 50.136 | 2004 | 49.769 | 2003 | 49.341 | 2002 | 48.907 | 2001 | 48.442 | 2000 | 47.793 | 1999 | 47.145 | 1998 | 46.376 | 1997 | 45.76 | 1996 | 45.076 | 1995 | 44.451 | 1994 | 44.032 | 1993 | 43.656 | 1992 | 43.149 | 1991 | 42.821 | 1990 | 42.648 | 1989 | 42.31 | 1988 | 41.985 | 1987 | 36.931 | 1986 | 36.86 | 1985 | 35.09 | 1984 | 34.86 | 1983 | 39.372 | 1982 | 39.227 | 1981 | 39.099 | 1980 | 41.436 | 1979 | 41.429 | 1978 | 41.49 | 1977 | 41.395 | 1976 | 41.374 | 1975 | 41.357 | 1974 | 40.627 | 1973 | 40.001 | 1972 | 39.845 | 1971 | 40.242 | 1970 | 40.268 | 1969 | 40.236 | 1968 | 40.164 | 1967 | 40.16 | 1966 | 40.109 | 1965 | 40.261 | 1964 | 40.228 | 1963 | 40.764 | 1962 | 40.644 | 1961 | 40.358 | 1960 | 40.033 |
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