Year	Number
1996	13.8991
1997	15.01908
1998	12.51305
1999	12.56177
2000	12.50358
2001	13.38953
2002	13.40359
2003	14.35651
2004	11.65512
2005	12.05634
2006	11.61747
2007	11.4941
2008	11.28118
2009	10.98837
2010	10.99381
2011	10.89304
2012	10.77782
2013	12.99036
2014	13.09048
2015	13.04281
2016	15.15482