Year	Number of
1990	202.13
1991	209.82
1992	217.83
1993	226.17
1994	234.98
1995	244
1996	250.51
1997	257.32
1998	264.96
1999	272.96
2000	280.7
2001	289
2002	298.16
2003	308.61
2004	319.66
2005	331.26
2006	345.47
2007	360.6
2008	377.37
2009	395.36
2010	415.33
2011	431.56
2012	448.93
2013	467.28
2014	487.22
2015	508.81
2016	531.09