Year | Value | 2021 | 33.021510693263 | 2020 | 32.876372325325 | 2019 | 33.369084995931 | 2018 | 32.946207624983 | 2017 | 32.734392115248 | 2016 | 32.76292360907 | 2015 | 32.955477287944 | 2014 | 33.071969659291 | 2013 | 32.931860423449 | 2012 | 33.057599723635 | 2011 | 33.243670355884 | 2010 | 33.082049502275 | 2009 | 33.890440694471 | 2008 | 33.623931276833 | 2007 | 33.38362426474 | 2006 | 34.218841629271 | 2005 | 34.117650257722 | 2004 | 34.189561846211 | 2003 | 34.549236378665 | 2002 | 35.156643847226 | 2001 | 36.198300585808 | 2000 | 37.991111062844 | 1999 | 38.577893771883 | 1998 | 38.589102347725 | 1997 | 39.157964846426 | 1996 | 39.048509302888 | 1995 | 39.153401804727 | 1994 | 39.652237497138 | 1993 | 39.996126546101 | 1992 | 40.407432852489 | 1991 | 44.418336162988 | 1990 | 44.486103186894 | 1989 | 44.518705680985 | 1988 | 45.393621206571 | 1987 | 45.355020755894 | 1986 | 45.243780014651 | 1985 | 45.231570665003 | 1984 | 45.180020077597 | 1983 | 45.052500203489 | 1982 | 45.026114088042 | 1981 | 45.059417222855 | 1980 | 45.184964119538 | 1979 | 45.311864130877 | 1978 | 45.418661747352 | 1977 | 45.478961504029 | 1976 | 45.537906431003 | 1975 | 45.585502489047 | 1974 | 45.703511794148 | 1973 | 45.784897521805 | 1972 | 45.931391831586 | 1971 | 46.151133296258 | 1970 | 46.329553469698 | 1969 | 46.433367243133 | 1968 | 46.691081722618 | 1967 | 46.728426877899 | 1966 | 46.962442524448 | 1965 | 46.993001302083 | 1964 | 47.363995171507 | 1963 | 47.361282534688 | 1962 | 47.603352864583 | 1961 | 47.800081378001 |
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