Year	Number of
1990	411.93
1991	421.97
1992	426.79
1993	428.81
1994	430.88
1995	434.02
1996	425.94
1997	414.37
1998	409.39
1999	411.35
2000	400.46
2001	389.54
2002	381.61
2003	379.96
2004	375.43
2005	366.15
2006	353.7
2007	336.72
2008	337.19
2009	329.95
2010	324.22
2011	320.27
2012	314.53
2013	310.57
2014	309.78
2015	309.38
2016	311.91