Year	Number of
1990	40.43
1991	42.13
1992	43.93
1993	45.88
1994	47.96
1995	50.18
1996	51.05
1997	52
1998	53.11
1999	54.3
2000	55.6
2001	56.65
2002	57.84
2003	59.2
2004	60.6
2005	62.04
2006	64.63
2007	67.22
2008	69.89
2009	72.78
2010	75.97
2011	79.02
2012	82.38
2013	85.89
2014	89.51
2015	93.2
2016	97.13