Year	Number of
1990	241.5
1991	264.64
1992	288.56
1993	309.24
1994	338.81
1995	367.95
1996	391.28
1997	409.23
1998	426.34
1999	434.16
2000	435.23
2001	436.07
2002	433.03
2003	438.86
2004	428.41
2005	426.17
2006	429.09
2007	428.3
2008	429.55
2009	433.96
2010	438.77
2011	445.02
2012	449.73
2013	456.69
2014	462.59
2015	475.49
2016	492.29