Year	Number of
1990	327.5
1991	345.23
1992	362.95
1993	383.08
1994	407.33
1995	431.11
1996	451.13
1997	466.01
1998	478.57
1999	474.12
2000	474.97
2001	475.8
2002	479.82
2003	485.95
2004	494.49
2005	504.56
2006	515.19
2007	526.85
2008	542.48
2009	560.93
2010	579.49
2011	600.01
2012	618.5
2013	637.2
2014	657.36
2015	678
2016	700.75