Year Number 1996 35.6783905029297 1998 33.5 2000 26.3681583404541 2002 34.3283576965332 2003 28.8557205200195 2004 31.730770111084 2005 29.6650714874268 2006 26.7942581176758 2007 24.8803825378418 2008 24.0384616851807 2009 33.6492881774902 2010 33.6492881774902 2011 35.2112693786621 2012 31.9248828887939 2013 33.8028182983398 2014 33.1730766296387 2015 31.9047622680664 2016 30.4761905670166 2017 30.4761905670166 2018 29.5238094329834 2019 31.9047622680664 2020 30 2021 27.619047164917 2022 18.3962268829346