Year	Number of
1990	831.8
1991	813.36
1992	801.11
1993	779.12
1994	736.59
1995	697.29
1996	690.67
1997	661.87
1998	625.15
1999	588.84
2000	547.74
2001	507.26
2002	497.53
2003	484.95
2004	481.77
2005	491.38
2006	483.04
2007	490.24
2008	498.8
2009	497.09
2010	497.19
2011	505.81
2012	510.31
2013	511.36
2014	509.85
2015	492.67
2016	484.19