Year	Number of
1990	606.67
1991	589.04
1992	567.94
1993	547.9
1994	529.54
1995	515.46
1996	509.11
1997	494.9
1998	483.62
1999	466.97
2000	456.09
2001	447.86
2002	445.87
2003	443.21
2004	436.34
2005	434.62
2006	435.19
2007	430.15
2008	426.94
2009	427.03
2010	425.95
2011	426.86
2012	428.61
2013	433.47
2014	437.87
2015	439.55
2016	444.07