Year	Number of
1990	155
1991	161.9
1992	170.17
1993	180.66
1994	191.36
1995	204.98
1996	220.17
1997	242.25
1998	260.49
1999	283.54
2000	305.04
2001	322.78
2002	340.68
2003	360.36
2004	377.43
2005	398.03
2006	411.48
2007	423.57
2008	439.23
2009	456.07
2010	472.44
2011	487.05
2012	503.16
2013	523.55
2014	540.92
2015	554.08
2016	568.68