Year	Number of
1990	38.39
1991	39.71
1992	41.11
1993	42.62
1994	44.21
1995	45.93
1996	47.48
1997	49.01
1998	50.67
1999	52.19
2000	53.82
2001	55.44
2002	57.08
2003	58.93
2004	60.74
2005	62.79
2006	64.64
2007	66.69
2008	68.94
2009	71.45
2010	73.75
2011	76.75
2012	79.96
2013	83.31
2014	86.88
2015	90.65
2016	94.73