Year	Number of
1990	163.85
1991	168.7
1992	170.16
1993	181.38
1994	187.96
1995	196.33
1996	200.46
1997	211.36
1998	220.54
1999	222.97
2000	233.95
2001	240.64
2002	251.31
2003	260.73
2004	272.56
2005	285.54
2006	294.1
2007	302.83
2008	312.88
2009	324.26
2010	337.11
2011	348.81
2012	361.42
2013	375.6
2014	391.08
2015	407.75
2016	423.93