Year	Number of
1990	279.17
1991	282.11
1992	292.54
1993	304.76
1994	306.91
1995	317.47
1996	313.63
1997	311.52
1998	310.03
1999	321.7
2000	351.93
2001	371.35
2002	391.71
2003	417.83
2004	432.66
2005	443.01
2006	453.47
2007	454.74
2008	452.98
2009	452.56
2010	459.44
2011	477.64
2012	499.79
2013	531.86
2014	565.04
2015	593.33
2016	621.6