| Year | Value | | 2022 | 15.147956089723 | | 2021 | 7.3528124338022 | | 2020 | 3.7960402611125 | | 2019 | 7.3010695355072 | | 2018 | 6.8242479014552 | | 2017 | 4.3014310530234 | | 2016 | 0.7332722273144 | | 2015 | 5.7356828193832 | | 2014 | 12.253980812976 | | 2013 | 10.490656758824 | | 2012 | 14.330334832584 | | 2011 | 8.411214953271 | | 2010 | 10.046206588165 | | 2009 | 7.619505935194 | | 2008 | 27.955665024631 | | 2007 | 9.6309630963097 | | 2006 | 5.0951666166316 | | 2005 | 12.716567406605 | | 2004 | 8.2411544941762 | | 2003 | 5.1289949942242 | | 2002 | 0.91707468718427 | | 2001 | 6.2773602048401 | | 2000 | 11.595538759333 | | 1999 | 7.5649415030737 | | 1998 | 9.3570421771655 | | 1997 | 36.556114894877 | | 1996 | 46.88995215311 | | 1995 | 0.043516100957192 | | 1994 | 87.580009329808 | | 1993 | 268.15048888278 |
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