Year	Number of
1990	541.47
1991	531.2
1992	499.34
1993	476.11
1994	440.84
1995	400.92
1996	387.6
1997	384.17
1998	404.84
1999	408.7
2000	416.42
2001	407.82
2002	439.8
2003	477.93
2004	503.26
2005	533.81
2006	546.52
2007	544.49
2008	545.34
2009	550.41
2010	551.13
2011	554.54
2012	548.57
2013	529.33
2014	511.39
2015	493.67
2016	483.12