Year	Number of
1990	91.11
1991	89.86
1992	87.56
1993	88.26
1994	87.71
1995	86.85
1996	83.68
1997	84.76
1998	82.39
1999	81.8
2000	80.55
2001	81.36
2002	82.02
2003	84.53
2004	81.76
2005	80.17
2006	80.63
2007	80.2
2008	81.01
2009	83.29
2010	86.18
2011	88.57
2012	89.91
2013	91.42
2014	95.22
2015	97.84
2016	99.54