Year	Number of
1990	455.98
1991	477.73
1992	479.02
1993	478.38
1994	480.23
1995	494.8
1996	504.07
1997	521.68
1998	526.91
1999	530.41
2000	524.72
2001	527.08
2002	527.97
2003	535.7
2004	535.27
2005	533.03
2006	537.09
2007	550.08
2008	549.57
2009	547.92
2010	560.94
2011	566.39
2012	575.45
2013	575.27
2014	573.49
2015	579.18
2016	584.35