Year	Number
1993	17.59747
1994	15.67941
1995	15.07139
1996	13.99306
1998	13.74634
1999	14.12375
2001	12.99654
2002	12.4976
2003	12.65035
2004	15.09636
2005	15.13255
2006	15.18873
2007	17.64818
2008	17.44067
2009	17.15585
2010	17.01688
2011	16.7077
2012	16.78039
2013	16.8859
2014	16.74887
2015	16.90462
2016	13.80157