Year	Number of
1990	492.57
1991	492.73
1992	491.28
1993	487.99
1994	490.42
1995	489.28
1996	482.13
1997	479.29
1998	481.32
1999	486.42
2000	494.18
2001	493.82
2002	497.22
2003	504.97
2004	514.16
2005	524.55
2006	530.92
2007	530.96
2008	538.66
2009	541.66
2010	552.67
2011	557.44
2012	566.75
2013	576.45
2014	588.85
2015	598.71
2016	609.76