Year	Number of
1990	70.22
1991	75.36
1992	80.8
1993	86.77
1994	93.27
1995	100.4
1996	109
1997	118.49
1998	129.41
1999	141.32
2000	154.32
2001	163.7
2002	173.72
2003	185.1
2004	197.23
2005	210.16
2006	221.04
2007	232.57
2008	245.09
2009	258.29
2010	272.22
2011	284.75
2012	297.86
2013	311.42
2014	325.88
2015	341.34
2016	357.12