Year	Number of
1990	10.74
1991	11.73
1992	12.97
1993	14.38
1994	15.85
1995	17.29
1996	18.35
1997	19.15
1998	19.74
1999	20.3
2000	20.92
2001	22.55
2002	24.62
2003	27.11
2004	29.92
2005	33.04
2006	35.97
2007	39.17
2008	43.31
2009	49.17
2010	57.58
2011	65.18
2012	75.89
2013	88.87
2014	102.71
2015	116.28
2016	130.12