Year	Number of
1990	161.42
1991	167.51
1992	173.96
1993	180.82
1994	188.09
1995	195.86
1996	203.98
1997	212.58
1998	221.73
1999	231.44
2000	241.82
2001	249.26
2002	257.04
2003	265.24
2004	273.95
2005	283.37
2006	290.55
2007	298.16
2008	306.51
2009	315.38
2010	324.88
2011	335.63
2012	347.09
2013	359.01
2014	371.76
2015	385.4
2016	400.46