| Year | Value | | 2022 | 22.956222513206 | | 2021 | 3.7556203665888 | | 2020 | 5.1040726295992 | | 2019 | 3.3225588125693 | | 2018 | 2.040392668902 | | 2017 | 0.82547860756803 | | 2016 | 1.596912275832 | | 2015 | 1.2773542710299 | | 2014 | 4.1292430687377 | | 2013 | 6.3714271778295 | | 2012 | 4.2551267783209 | | 2011 | 7.5689885610998 | | 2010 | 5.9825452155008 | | 2009 | 0.14118767498039 | | 2008 | 7.6288088757752 | | 2007 | 4.661972694697 | | 2006 | 6.5455943905279 | | 2005 | 7.1654175994664 | | 2004 | 10.462266731421 | | 2003 | 15.489352923353 | | 2002 | 10.631344632333 | | 2001 | 7.8118079478347 | | 2000 | 25.084641428132 | | 1999 | 125.27212839928 | | 1998 | 90.980734562288 | | 1997 | 27.508862449145 | | 1996 | 13.024415696346 | | 1995 | 19.593918987858 | | 1994 | 6.7844807862023 | | 1993 | 6.2672224151903 | | 1992 | 9.8645296699103 | | 1991 | 13.441558441559 | | 1990 | 35.642982971227 | | 1989 | 61.332596510619 |
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