Year	Number
2002	15.99716
2003	17.43037
2004	17.14922
2005	17.5744
2006	18.20001
2007	17.83324
2008	16.86276
2009	17.41308
2010	18.42957
2011	18.35537
2012	15.93259
2013	16.09587