Year	Number of
1990	277.01
1991	295.93
1992	316.4
1993	337.61
1994	360.37
1995	385.39
1996	416.5
1997	450.86
1998	488.63
1999	529.59
2000	574.81
2001	613.09
2002	653.35
2003	696
2004	741.57
2005	791.4
2006	851.33
2007	917.27
2008	989.3
2009	1067.26
2010	1152.89
2011	1213.45
2012	1275.81
2013	1340.66
2014	1408.08
2015	1478.19
2016	1552.03