Year	Number of
1990	186.65
1991	195.18
1992	203.34
1993	216.05
1994	228.6
1995	241.43
1996	253.86
1997	266.23
1998	278.72
1999	289.67
2000	294.76
2001	299.41
2002	304.85
2003	315.63
2004	323.08
2005	331.47
2006	345.64
2007	367.09
2008	393.67
2009	416.99
2010	440.49
2011	443.65
2012	446.67
2013	448.64
2014	451.25
2015	457.89
2016	464.88