Year	Number of
1990	420.56
1991	416.86
1992	410.36
1993	412.64
1994	416.97
1995	409.54
1996	400.8
1997	391.98
1998	386.63
1999	387.12
2000	383.23
2001	381.33
2002	376.66
2003	377.78
2004	380.14
2005	384
2006	386.95
2007	388.71
2008	392.35
2009	396.68
2010	403.84
2011	410.43
2012	415.78
2013	420.13
2014	424.91
2015	430.81
2016	438.21