Year Number 1996 57.7889442443848 1998 59 2000 56.7164192199707 2002 57.2139320373535 2003 62.6865653991699 2004 57.211540222168 2005 56.9377975463867 2006 52.6315803527832 2007 55.9808616638184 2008 53.3653831481934 2009 49.7630348205566 2010 47.3933639526367 2011 46.478874206543 2012 40.8450698852539 2013 36.6197166442871 2014 40.3846168518066 2015 36.1904754638672 2016 31.9047622680664 2017 31.4285717010498 2018 30.4761905670166 2019 27.1428565979004 2020 24.2857151031494 2021 25.238094329834 2022 23.5849056243896