Year	Number of
1990	297.31
1991	298.86
1992	309.15
1993	314.58
1994	321.22
1995	329.13
1996	332.65
1997	342.03
1998	352.25
1999	353.56
2000	354.66
2001	353.81
2002	359.39
2003	366.97
2004	379.05
2005	390.18
2006	402.98
2007	411.59
2008	421.38
2009	437.02
2010	462.02
2011	484.99
2012	513.43
2013	542.37
2014	567.36
2015	590.59
2016	609.67