Year	Number of
1990	194.66
1991	192.63
1992	192.13
1993	192.22
1994	192.46
1995	192.49
1996	200.54
1997	208.55
1998	218.35
1999	230.37
2000	245.72
2001	270.79
2002	302.09
2003	340.32
2004	382.12
2005	426.49
2006	451.82
2007	475.33
2008	501
2009	532.68
2010	573.84
2011	613.27
2012	662
2013	717.19
2014	770.71
2015	818.52
2016	873.35