Year	Number of
1990	134.26
1991	144.44
1992	157.93
1993	173.77
1994	189.9
1995	205.5
1996	214.37
1997	221.33
1998	227.32
1999	234.13
2000	242.97
2001	252.75
2002	265.04
2003	278.87
2004	293.05
2005	307.2
2006	319.97
2007	331.58
2008	343.37
2009	356.38
2010	371.73
2011	386.93
2012	404.97
2013	424.81
2014	445.79
2015	467.34
2016	490.45