Year	Number of
1990	221.74
1991	225.72
1992	230.66
1993	236.66
1994	240.9
1995	245.35
1996	247.21
1997	249.24
1998	251.9
1999	254.23
2000	259.18
2001	253.48
2002	249.21
2003	245.46
2004	241.69
2005	247.78
2006	251.81
2007	255.81
2008	260.13
2009	264.42
2010	268.61
2011	272.37
2012	276.31
2013	280.46
2014	284.78
2015	289.38
2016	293.02