Year	Number of
1990	298.92
1991	300.46
1992	309.03
1993	323.58
1994	328.95
1995	339.22
1996	347.38
1997	356.88
1998	362.19
1999	373
2000	389.2
2001	387.98
2002	397.15
2003	400.71
2004	408.85
2005	422.14
2006	434.21
2007	446.85
2008	450.28
2009	459.92
2010	470.58
2011	475.1
2012	479.14
2013	480.38
2014	481.76
2015	484.5
2016	487.34