Year	Number of
1990	226.87
1991	235.11
1992	244
1993	254.98
1994	266.58
1995	278.9
1996	290.79
1997	303.55
1998	319.09
1999	335.46
2000	353.13
2001	362.5
2002	372.78
2003	383.25
2004	394.46
2005	407.37
2006	419.34
2007	430.56
2008	439.49
2009	448.47
2010	457.75
2011	462.49
2012	468.59
2013	474.27
2014	485.21
2015	497.01
2016	512.83