Year Number 1996 40.2010040283203 1998 35.5 2000 30.348258972168 2002 25.3731346130371 2003 27.3631839752197 2004 29.3269233703613 2005 31.1004791259766 2006 28.7081336975098 2007 29.6650714874268 2008 31.25 2009 32.7014236450195 2010 33.1753540039063 2011 33.3333320617676 2012 34.7417831420898 2013 39.9061050415039 2014 43.269229888916 2015 42.3809509277344 2016 38.0952377319336 2017 39.0476188659668 2018 40.9523811340332 2019 44.2857131958008 2020 48.0952377319336 2021 40.9523811340332 2022 41.0377349853516