Year	Number of
1990	231.97
1991	243.71
1992	255.82
1993	265.28
1994	286.83
1995	294.95
1996	301.21
1997	301.43
1998	310.26
1999	338.5
2000	348.6
2001	361.9
2002	370.23
2003	383.06
2004	393.11
2005	390.3
2006	400.07
2007	411.6
2008	420.93
2009	428.06
2010	437.3
2011	439.59
2012	447.58
2013	451.72
2014	467.39
2015	461.14
2016	454.49