Year	Number of
1990	41.29
1991	42.71
1992	43.41
1993	46.43
1994	48.26
1995	50.98
1996	53
1997	53.68
1998	54.42
1999	55.62
2000	56.93
2001	58.25
2002	59.86
2003	62.06
2004	65.53
2005	69.02
2006	71.41
2007	72.55
2008	74.18
2009	77.6
2010	81.2
2011	83.98
2012	87.8
2013	90.39
2014	93.2
2015	96.1
2016	98.99