Year	Number of
1990	69.52
1991	71.6
1992	73.74
1993	75.8
1994	77.95
1995	80.28
1996	84.57
1997	89.27
1998	94.39
1999	99.95
2000	106.04
2001	112.17
2002	118.79
2003	126.28
2004	134.33
2005	143.05
2006	152.56
2007	162.65
2008	173.49
2009	185.13
2010	197.87
2011	201.42
2012	205.36
2013	209.29
2014	213.52
2015	218.01
2016	222.38