Year	Number of
1990	521.67
1991	512.75
1992	484.09
1993	462.78
1994	428.91
1995	389.19
1996	377.65
1997	377.53
1998	403.04
1999	411.27
2000	422.3
2001	415.65
2002	452.45
2003	496.97
2004	526.53
2005	555.78
2006	569.14
2007	566.93
2008	569.26
2009	575.06
2010	577.92
2011	584.47
2012	579.27
2013	558
2014	538.68
2015	516.36
2016	502.9