Year | Value | 2022 | 35.479396234881 | 2021 | 35.339735569257 | 2020 | 33.107732277981 | 2019 | 33.13725966032 | 2018 | 33.89186802857 | 2017 | 33.734889336401 | 2016 | 33.083093964369 | 2015 | 33.812815398553 | 2014 | 35.110833698218 | 2013 | 35.162631563785 | 2012 | 36.318522083719 | 2011 | 37.056520218971 | 2010 | 37.676273380416 | 2009 | 36.390884599676 | 2008 | 38.811088751647 | 2007 | 37.978789895561 | 2006 | 36.940068639909 | 2005 | 35.056414912345 | 2004 | 34.625032407353 | 2003 | 32.503867411236 | 2002 | 30.742475483868 | 2001 | 29.855222477641 | 2000 | 29.474812355365 | 1999 | 28.597502359741 | 1998 | 29.566637169379 | 1997 | 30.477955138004 | 1996 | 30.464827161525 | 1995 | 30.916481863317 | 1994 | 32.801836479831 | 1993 | 33.101238680389 | 1992 | 31.934591507575 | 1991 | 30.677270905351 | 1990 | 29.96715307077 | 1989 | 31.873109014642 | 1988 | 32.547095285796 | 1987 | 31.271338325246 | 1986 | 29.752462959138 | 1985 | 30.791693330464 | 1984 | 29.445030320185 | 1983 | 28.217123674896 | 1982 | 28.392463307364 |
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