Year	Number of
1990	73.09
1991	74.86
1992	77.21
1993	80.16
1994	83.39
1995	86.62
1996	90.06
1997	93.44
1998	96.83
1999	100.11
2000	103.8
2001	107.52
2002	111.56
2003	115.93
2004	120.46
2005	125.43
2006	129.68
2007	134.26
2008	139.05
2009	144.26
2010	149.76
2011	155.49
2012	161.81
2013	168.64
2014	176.33
2015	184.55
2016	192.96