Year	Number of
1990	702.71
1991	674.7
1992	660.01
1993	648.35
1994	632.74
1995	623.32
1996	615.23
1997	595.07
1998	572.15
1999	568.61
2000	562.32
2001	549.1
2002	536.85
2003	523.93
2004	521.54
2005	501.09
2006	488.81
2007	483.17
2008	475.04
2009	467.5
2010	460.69
2011	466.8
2012	475.68
2013	475.31
2014	471.23
2015	470.51
2016	473.09