Year	Number of
1990	248.64
1991	251.07
1992	252.39
1993	257.55
1994	260.5
1995	266.36
1996	264.2
1997	259.47
1998	263.06
1999	246.86
2000	237.68
2001	252.22
2002	251.49
2003	241.6
2004	235.75
2005	239.25
2006	245.16
2007	252.78
2008	266.4
2009	278.38
2010	290.04
2011	309.56
2012	320.64
2013	328.51
2014	327.73
2015	323.26
2016	321.94