Year | Value | 2020 | 36.431424393321 | 2019 | 32.583059620912 | 2018 | 31.710750976806 | 2017 | 30.609175764779 | 2016 | 29.85343218752 | 2015 | 25.6840516373 | 2014 | 24.470463331097 | 2013 | 23.188288431247 | 2012 | 22.23688702469 | 2011 | 22.58420544275 | 2010 | 25.072769640143 | 2009 | 29.342933472156 | 2008 | 29.336054305991 | 2007 | 26.455799798105 | 2006 | 27.561299607136 | 2005 | 25.361124285461 | 2004 | 25.318907352141 | 2003 | 22.643423828 | 2002 | 20.661943775871 | 2001 | 17.115766723304 | 2000 | 17.15599146582 | 1999 | 14.902322335601 | 1998 | 18.687561394652 | 1997 | 11.003682725841 | 1996 | 10.981665480573 | 1995 | 9.669850078847 | 1994 | 3.4152802402237 | 1993 | 5.0305261072974 | 1992 | 6.9308238759322 | 1991 | 5.171566904199 | 1990 | 8.2511600539868 |
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