Year	Number of
1990	293
1991	286.15
1992	288.35
1993	292.69
1994	287.74
1995	282.29
1996	282.53
1997	276.88
1998	267.33
1999	257.04
2000	252.35
2001	251.44
2002	243.5
2003	241
2004	238.01
2005	231.68
2006	228.84
2007	229.76
2008	231.11
2009	233.78
2010	234.88
2011	242.73
2012	253.81
2013	261.68
2014	264.6
2015	267.99
2016	271.74