Year Number 1996 6.45161294937134 1998 5.34759378433228 2000 8.51063823699951 2002 17.4603176116943 2003 10.0529098510742 2004 19.7044334411621 2005 17.0731716156006 2006 12.1951217651367 2007 14.5631065368652 2008 17.9611644744873 2009 21.0526313781738 2010 21.4285717010498 2011 22.748815536499 2012 18.9573459625244 2013 21.3270149230957 2014 15.384614944458 2015 14.7619047164917 2016 13.3333330154419 2017 14.7619047164917 2018 13.8095235824585 2019 11.9047622680664 2020 6.66666650772095 2021 4.7619047164917 2022 4.71698093414307