Year	Number of
1990	582.44
1991	559.54
1992	546.12
1993	535.13
1994	514.54
1995	499.95
1996	492.29
1997	479.79
1998	467.39
1999	471.92
2000	471.56
2001	467.14
2002	463.41
2003	453.3
2004	451.06
2005	433.09
2006	423.65
2007	416.97
2008	409.18
2009	404.41
2010	398.9
2011	402.49
2012	409.85
2013	408.73
2014	404.18
2015	404.4
2016	405.88