Year	Number of
1990	38.77
1991	38.81
1992	39.37
1993	40.08
1994	40.67
1995	41.26
1996	41.84
1997	42.31
1998	42.97
1999	42.98
2000	43.38
2001	44.44
2002	46.2
2003	48.61
2004	51.48
2005	53.88
2006	57.61
2007	61.64
2008	63.34
2009	65.78
2010	69.23
2011	72.79
2012	77.18
2013	82.36
2014	87.28
2015	91.5
2016	96.35