Year	Number of
1990	514.95
1991	538.63
1992	553.4
1993	570.09
1994	561.96
1995	567.42
1996	548.03
1997	540.23
1998	519.19
1999	494.71
2000	477.82
2001	474.19
2002	464.84
2003	451.25
2004	451.18
2005	448.02
2006	441.66
2007	434.69
2008	435.15
2009	438.65
2010	444.41
2011	445.52
2012	429.4
2013	422.65
2014	417.09
2015	428.46
2016	439.12