Year	Number of
1990	343.92
1991	347.18
1992	353.17
1993	364.48
1994	376.22
1995	392.26
1996	392.17
1997	397.17
1998	403.6
1999	408.8
2000	418.3
2001	427.73
2002	435.55
2003	443.98
2004	451.24
2005	453.53
2006	452.75
2007	458.95
2008	468.12
2009	481.86
2010	493.94
2011	504.56
2012	513.24
2013	523.36
2014	536.98
2015	552.38
2016	569.89