| Year | Value | | 2022 | 13.823873878839 | | 2021 | 5.8783552085581 | | 2020 | 2.7461507821378 | | 2019 | 2.8898607371835 | | 2018 | 2.6132342483074 | | 2017 | 3.1531861748501 | | 2016 | 1.2754316836741 | | 2015 | 4.003578206951 | | 2014 | 2.9813086893367 | | 2013 | 3.9847123554813 | | 2012 | 3.373498083874 | | 2011 | 7.6686295560774 | | 2010 | 6.1425536024725 | | 2009 | 3.4667237320779 | | 2008 | 10.444128376489 | | 2007 | 8.402534190059 | | 2006 | 6.9971290353559 | | 2005 | 7.5799992912576 | | 2004 | 6.882054389819 | | 2003 | 4.7215533660534 | | 2002 | 5.6989904786131 | | 2001 | 7.8575385219659 | | 2000 | 13.180890586573 | | 1999 | 19.19267582189 | | 1998 | 10.577161148251 | | 1997 | 15.940599414943 | | 1996 | 38.829301338285 | | 1995 | 85.886916205658 | | 1994 | 222.24101418432 |
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