Year | Value | 2021 | 32.171369310897 | 2020 | 25.72174927534 | 2019 | 30.58232676565 | 2018 | 28.824458682185 | 2017 | 28.855747503025 | 2016 | 24.946144294513 | 2015 | 23.599333278515 | 2014 | 31.406894178486 | 2013 | 33.3457985556 | 2012 | 36.530133872583 | 2011 | 26.879759704251 | 2010 | 30.275129057249 | 2009 | 28.585930987145 | 2008 | 43.726163747892 | 2007 | 48.088998443176 | 2006 | 42.208622278051 | 2005 | 35.966348780195 | 2004 | 24.105475623223 | 2003 | 25.547485309056 | 2002 | 22.827817451957 | 2001 | 18.239961245019 | 2000 | 25.733251126143 | 1999 | 7.3556797061149 | 1998 | 8.8509171758626 | 1997 | 16.965612573196 | 1996 | 18.607832652052 | 1995 | 18.639429280057 | 1994 | 16.566354824706 | 1993 | 11.517414028799 | 1992 | 12.035378414689 | 1991 | 15.532638128709 | 1990 | 36.179577464789 | 1989 | 23.817718730639 | 1988 | 31.082537174054 | 1987 | 24.886304287777 | 1986 | 22.802125991113 | 1985 | 34.301944505134 | 1984 | 42.335709908039 | 1983 | 48.967530620936 | 1982 | 50.145914799539 | 1981 | 54.490375035491 | 1980 | 51.074259524865 |
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