Year	Number of
1990	235.8
1991	237.26
1992	232.42
1993	237.71
1994	238.53
1995	242.44
1996	239.88
1997	243.11
1998	244.76
1999	245.22
2000	243
2001	236.71
2002	241.34
2003	238.84
2004	235.66
2005	231.58
2006	239.44
2007	241.54
2008	242.99
2009	247.26
2010	252.82
2011	249.73
2012	251.88
2013	244.73
2014	244.67
2015	242.4
2016	240.04