Year | Value | 2021 | 54.975 | 2020 | 55.48 | 2019 | 55.912 | 2018 | 55.95 | 2017 | 55.309 | 2016 | 55.544 | 2015 | 55.566 | 2014 | 54.973 | 2013 | 55.751 | 2012 | 55.865 | 2011 | 54.94 | 2010 | 54.812 | 2009 | 53.891 | 2008 | 53.538 | 2007 | 52.856 | 2006 | 52.016 | 2005 | 51.545 | 2004 | 50.917 | 2003 | 50.253 | 2002 | 47.492 | 2001 | 46.881 | 2000 | 46.028 | 1999 | 43.223 | 1998 | 18.385 | 1997 | 32.242 | 1996 | 31.297 | 1995 | 30.948 | 1994 | 44.384 | 1993 | 22.704 | 1992 | 22.724 | 1991 | 30.148 | 1990 | 29.935 | 1989 | 29.68 | 1988 | 12.407 | 1987 | 21.912 | 1986 | 33.632 | 1985 | 33.154 | 1984 | 32.673 | 1983 | 35.491 | 1982 | 39.113 | 1981 | 38.783 | 1980 | 38.417 | 1979 | 37.919 | 1978 | 37.649 | 1977 | 37.325 | 1976 | 36.84 | 1975 | 36.746 | 1974 | 36.514 | 1973 | 36.479 | 1972 | 31.907 | 1971 | 31.582 | 1970 | 26.399 | 1969 | 26.086 | 1968 | 26.708 | 1967 | 26.406 | 1966 | 26.084 | 1965 | 29.288 | 1964 | 33.149 | 1963 | 28.826 | 1962 | 29.119 | 1961 | 28.84 | 1960 | 28.662 |
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