Year Number 1996 5.02512550354004 1998 6 2000 4.47761201858521 2002 9.45273590087891 2003 11.9402980804443 2004 12.9807691574097 2005 16.2679424285889 2006 11.4832534790039 2007 11.9617223739624 2008 12.9807691574097 2009 13.7440757751465 2010 12.3222751617432 2011 11.7370891571045 2012 12.2065725326538 2013 16.4319248199463 2014 16.3461532592773 2015 14.7619047164917 2016 19.5238094329834 2017 20.4761905670166 2018 19.0476188659668 2019 20 2020 16.6666660308838 2021 21.4285717010498 2022 19.8113212585449