Year Number 1996 9.04255294799805 1998 7.97872352600098 2000 12.1693124771118 2002 9.5238094329834 2003 5.52763795852661 2004 3.88349509239197 2005 18.4466018676758 2006 17.8743953704834 2007 17.8743953704834 2008 13.4615383148193 2009 19.9052124023438 2010 12.3222751617432 2011 9.95260620117188 2012 10.4265403747559 2013 18.0094795227051 2014 29.5238094329834 2015 7.61904764175415 2016 8.5714282989502 2017 8.09523773193359 2018 11.3207550048828 2019 11.7924528121948 2020 12.7358493804932 2021 17.9245281219482 2022 18.8679237365723