Year	Number of
1990	518.16
1991	529.23
1992	536.21
1993	542.63
1994	541.98
1995	549.75
1996	553.27
1997	562.11
1998	564.78
1999	569.06
2000	564.78
2001	567.4
2002	561.92
2003	554.78
2004	561.43
2005	564.35
2006	568.04
2007	572.79
2008	582.1
2009	599.23
2010	592.63
2011	608.1
2012	608.29
2013	616.13
2014	628.1
2015	648.57
2016	668.62