Year	Number of
1990	36.2
1991	37.19
1992	38.36
1993	39.77
1994	41.08
1995	42.62
1996	43.75
1997	45.76
1998	47.62
1999	49.57
2000	51.8
2001	53.03
2002	54.52
2003	55.88
2004	57.17
2005	58.28
2006	59.09
2007	61.24
2008	62.25
2009	63.76
2010	65.48
2011	68.55
2012	70.53
2013	72.9
2014	75.93
2015	79.28
2016	82.3