Year	Number of
1990	224.4
1991	228.3
1992	227.03
1993	228.54
1994	226.17
1995	227.45
1996	224.95
1997	229.91
1998	230.21
1999	231.59
2000	229.45
2001	231.67
2002	230.62
2003	233.57
2004	237.67
2005	243.31
2006	246.16
2007	253.16
2008	250.36
2009	255.1
2010	251.76
2011	252.09
2012	251.52
2013	251.56
2014	247.86
2015	247.44
2016	247.79