Year	Number of
1990	353.2
1991	339.97
1992	329.92
1993	317.17
1994	304.51
1995	295.44
1996	280.78
1997	270.54
1998	261.01
1999	257.5
2000	252.51
2001	248.16
2002	251.9
2003	254.04
2004	251.52
2005	252.52
2006	248.62
2007	245.05
2008	240.66
2009	239.53
2010	233.76
2011	238.77
2012	240.7
2013	238.38
2014	236.93
2015	235.8
2016	236.04