Year	Number of
1990	59.12
1991	58.98
1992	58.42
1993	57.19
1994	55.34
1995	55.17
1996	53.88
1997	55.25
1998	53.6
1999	53.25
2000	53.21
2001	55.23
2002	58.8
2003	61.58
2004	63.53
2005	66.63
2006	69.97
2007	73.03
2008	75.93
2009	78.52
2010	81.25
2011	84.61
2012	88.48
2013	92.18
2014	95.97
2015	99.88
2016	104.87