Year	Number of
1990	24.85
1991	25.91
1992	27.1
1993	28.25
1994	29.54
1995	30.97
1996	32.48
1997	34.2
1998	36.02
1999	37.97
2000	40.18
2001	41.78
2002	43.86
2003	47.22
2004	52.69
2005	60.97
2006	68.58
2007	79.44
2008	92.61
2009	106.17
2010	119.05
2011	133.83
2012	146.83
2013	158.59
2014	170.45
2015	183.75
2016	200.01