Year	Number of
1990	207.5
1991	217.64
1992	229.59
1993	240.58
1994	250.22
1995	259.06
1996	267.42
1997	273.99
1998	284.9
1999	289.13
2000	300.82
2001	304.83
2002	319.25
2003	331.28
2004	342.02
2005	352.85
2006	367.35
2007	383.23
2008	399.8
2009	418.4
2010	439.85
2011	463.69
2012	487.25
2013	509.19
2014	535.06
2015	562.56
2016	590.75