Year	Number of
1990	183.73
1991	192.63
1992	202.5
1993	213.12
1994	224.39
1995	236.35
1996	247.05
1997	257.94
1998	269.27
1999	281.44
2000	294.36
2001	304.51
2002	316.13
2003	329.42
2004	344.05
2005	360.15
2006	372.47
2007	385.61
2008	400.34
2009	416.04
2010	433.81
2011	451.73
2012	471.2
2013	491.59
2014	513.82
2015	538.03
2016	565.24