Year	Number of
1990	427.76
1991	425.67
1992	427.63
1993	435.41
1994	443.18
1995	456.47
1996	462.55
1997	474.05
1998	480.48
1999	490.47
2000	499.87
2001	508.95
2002	518.3
2003	524.95
2004	531.55
2005	536.91
2006	541.36
2007	536.33
2008	532.12
2009	522.56
2010	517.02
2011	516.43
2012	517.52
2013	524.12
2014	532.6
2015	543.2
2016	554.7