Year	Number of
1990	452.98
1991	443.26
1992	430.4
1993	426.91
1994	424.88
1995	426.59
1996	411.39
1997	410.87
1998	403.71
1999	398.67
2000	392.38
2001	390.4
2002	386.26
2003	388.2
2004	393.29
2005	398
2006	400.62
2007	410.43
2008	413.84
2009	427.4
2010	426.46
2011	437.06
2012	443.25
2013	448.76
2014	452.81
2015	463.4
2016	475.59