Year	Number of
1990	387.63
1991	395.71
1992	404.95
1993	413.94
1994	418.36
1995	420.41
1996	418.3
1997	421.22
1998	417.37
1999	421.08
2000	421.25
2001	421.02
2002	429.13
2003	433
2004	437.11
2005	442.58
2006	444.16
2007	446.13
2008	448.23
2009	450.71
2010	454.38
2011	456.26
2012	460.52
2013	465.05
2014	471.24
2015	479.03
2016	487.38