Year	Number of
1990	282.26
1991	280.64
1992	280.94
1993	282.81
1994	274.59
1995	269.73
1996	264.23
1997	269.48
1998	269.31
1999	267.23
2000	261.3
2001	257.26
2002	252.47
2003	252.85
2004	249.9
2005	242.73
2006	239.62
2007	235.52
2008	233.71
2009	233
2010	232.36
2011	227.73
2012	226.66
2013	227.15
2014	222.17
2015	230.21
2016	231.78