Year | Value | 2022 | 43.062365200426 | 2021 | 41.002345689961 | 2020 | 39.31401738205 | 2019 | 41.071385242994 | 2018 | 39.56020397304 | 2017 | 36.301701844626 | 2016 | 34.380498403689 | 2015 | 36.122942532813 | 2014 | 35.454966300106 | 2013 | 35.301028733593 | 2012 | 33.391238027669 | 2011 | 32.097951401206 | 2010 | 30.925363604115 | 2009 | 33.170672224193 | 2008 | 31.783362894643 | 2007 | 29.967222419298 | 2006 | 29.614455480667 | 2005 | 30.804824405818 | 2004 | 30.677944306492 | 2003 | 30.782165661582 | 2002 | 29.862885775098 | 2001 | 28.906784320681 | 2000 | 28.30681092586 | 1999 | 27.545193330968 | 1998 | 26.967186945725 | 1997 | 25.628494146861 | 1996 | 23.987539907769 | 1995 | 22.300576445548 | 1994 | 21.169359702022 | 1993 | 20.626445548067 | 1992 | 20.310092231288 | 1991 | 20.116273501242 | 1990 | 20.054061724016 | 1989 | 19.559772969138 | 1988 | 19.565094004966 | 1987 | 19.474813763746 | 1986 | 19.386129833274 | 1985 | 18.852917701312 | 1984 | 18.559728627173 | 1983 | 18.391229159276 | 1982 | 18.404576090812 | 1981 | 18.045406172402 | 1980 | 17.774920184463 | 1979 | 17.5 | 1978 | 17.326268180206 | 1977 | 17.138666193686 | 1976 | 16.843827598439 | 1975 | 16.608815182689 |
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