| Year | Value | | 2022 | 13.852259014427 | | 2021 | 6.6944589195764 | | 2020 | 2.7598094700813 | | 2019 | 3.1037294479678 | | 2018 | 2.6152447139767 | | 2017 | 3.6833294441225 | | 2016 | 4.0697539813063 | | 2015 | 4.8711226169622 | | 2014 | 4.0787988250271 | | 2013 | 4.8037627135404 | | 2012 | 3.3160556668765 | | 2011 | 7.8583333333334 | | 2010 | 6.6473533551786 | | 2009 | 3.436745279458 | | 2008 | 12.37985318729 | | 2007 | 8.5914668223897 | | 2006 | 7.7952597281658 | | 2005 | 7.8795798296388 | | 2004 | 6.9216578742885 | | 2003 | 4.9506155925683 | | 2002 | 5.8101436572182 | | 2001 | 8.3541377716134 | | 2000 | 15.940812435188 | | 1999 | 20.938173814012 | | 1998 | 10.517271866462 | | 1997 | 16.674320237839 | | 1996 | 39.270021182063 | | 1995 | 162.71715215038 | | 1994 | 486.42562379589 |
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