Year Number 1996 2 1998 4.47761201858521 2000 33.8308448791504 2002 34.3283576965332 2003 35.8208961486816 2004 33.6538467407227 2005 30.2884616851807 2006 31.25 2007 30.769229888916 2008 28.8461532592773 2009 21.3270149230957 2010 23.6966819763184 2011 31.9248828887939 2012 31.9248828887939 2013 30.9859161376953 2014 33.9901466369629 2015 32.5123138427734 2016 29.0640392303467 2017 28.5714282989502 2018 25.2427177429199 2019 25.1207733154297 2020 29.468599319458 2021 32.3671493530273 2022 32.3671493530273