Year	Number of
1990	232.61
1991	233.25
1992	233.16
1993	230.92
1994	233.4
1995	238.68
1996	235.82
1997	231.4
1998	229.73
1999	232.2
2000	231.66
2001	227.91
2002	224.67
2003	221.02
2004	220.45
2005	214.7
2006	211
2007	213.1
2008	216.13
2009	226.94
2010	229.57
2011	226.04
2012	228.1
2013	228.56
2014	227.98
2015	230.72
2016	233.42