Year Number 1996 8.15217399597168 1998 4.89130449295044 2000 3.80434775352478 2002 3.78378367424011 2003 2.16216206550598 2004 2.48756217956543 2005 1.96078431606293 2006 1.47058820724487 2007 2.42718458175659 2008 2.42718458175659 2009 2.39234447479248 2010 1.91387557983398 2011 1.89573454856873 2012 1.42180097103119 2013 1.42180097103119 2014 0.480769217014313 2015 0.952380955219269 2016 1.42857146263123 2017 1.90476191043854 2018 2.85714292526245 2019 2.38095235824585 2020 1.90476191043854 2021 1.90476191043854 2022 1.88679242134094