Year	Number of
1990	404.37
1991	412.12
1992	420.88
1993	430.3
1994	440.4
1995	451.53
1996	463.59
1997	476.81
1998	490.93
1999	505.97
2000	522.53
2001	525.41
2002	529.23
2003	533.58
2004	538.63
2005	545.09
2006	549.9
2007	555.02
2008	561.73
2009	569.24
2010	578.16
2011	585.86
2012	595.05
2013	604.95
2014	615.73
2015	627.4
2016	639.35