Year	Number of
1990	217.1
1991	226.19
1992	237.55
1993	249.52
1994	261.03
1995	270.95
1996	279.73
1997	287.79
1998	298.35
1999	304.61
2000	313.66
2001	322.91
2002	333.94
2003	346.16
2004	360.46
2005	380.19
2006	373.59
2007	373.3
2008	376.9
2009	383.26
2010	392.12
2011	401.65
2012	417.45
2013	435.55
2014	464.11
2015	473.18
2016	484.51