Year	Number of
1990	350.07
1991	361.49
1992	374.17
1993	387.8
1994	402.16
1995	417.4
1996	431.24
1997	445.93
1998	461.68
1999	478.62
2000	497.32
2001	491.67
2002	486.39
2003	482.09
2004	478.17
2005	474.95
2006	488.9
2007	503.14
2008	517.79
2009	531.84
2010	545.39
2011	556.31
2012	568.13
2013	579.16
2014	591.89
2015	606.77
2016	621.72