Year	Number of
1990	528.21
1991	544.64
1992	555.98
1993	568.07
1994	569.09
1995	573.57
1996	581.86
1997	586.81
1998	586.9
1999	591.24
2000	587.39
2001	583.48
2002	583.52
2003	588.97
2004	582.16
2005	582.33
2006	588.29
2007	593.94
2008	601.76
2009	612.41
2010	621.48
2011	627.37
2012	632.18
2013	628.63
2014	618.71
2015	620.82
2016	612.61