Year	Number
2003	22.40761
2004	23.19403
2005	23.81542
2006	22.33103
2007	21.54642
2008	20.28825
2009	22.71092
2010	21.25037
2011	17.6932
2012	20.50943
2013	19.89063
2014	18.71932
2015	18.279
2016	19.23055