Year	Number of
1990	502.26
1991	514.03
1992	527.19
1993	535.88
1994	544.45
1995	554.4
1996	541.64
1997	531.17
1998	520.99
1999	511.4
2000	501.43
2001	516.65
2002	532.77
2003	549.43
2004	565.74
2005	583.12
2006	587.87
2007	592.63
2008	597.27
2009	602.23
2010	607.72
2011	603.08
2012	598.39
2013	593.37
2014	591.78
2015	590.63
2016	590.01