Year	Number of
1990	252.71
1991	255.5
1992	250.49
1993	245.34
1994	241.95
1995	241.6
1996	242.57
1997	246.65
1998	244.85
1999	246.71
2000	239.5
2001	242.08
2002	239.5
2003	240.42
2004	239.96
2005	237.14
2006	235.72
2007	238.66
2008	231.61
2009	231.33
2010	234.24
2011	235.04
2012	235.59
2013	236
2014	233.01
2015	234.23
2016	235.06