Year	Number of
1990	238.19
1991	250.34
1992	264.9
1993	280.63
1994	296
1995	310.19
1996	318.45
1997	324.97
1998	330.29
1999	335.43
2000	341.11
2001	344.53
2002	348.5
2003	353.16
2004	358.83
2005	365.76
2006	376.17
2007	388.27
2008	402.1
2009	417.2
2010	433.41
2011	448.25
2012	464.3
2013	481.33
2014	499.46
2015	518.71
2016	537.73