Year	Number of
1990	156.67
1991	166.19
1992	177.92
1993	188.68
1994	197.2
1995	205.93
1996	216.46
1997	224.93
1998	238.15
1999	241.91
2000	255.63
2001	253.52
2002	258.38
2003	266.98
2004	272.41
2005	278.22
2006	286.84
2007	295.13
2008	307.98
2009	321.66
2010	334.27
2011	351.76
2012	369.6
2013	384.11
2014	401.69
2015	420.98
2016	443.95