Year	Number of
1990	139.78
1991	138.82
1992	137.75
1993	135.26
1994	135.94
1995	137.97
1996	138.58
1997	144.27
1998	142.78
1999	145.75
2000	148.38
2001	155.62
2002	168.64
2003	177.13
2004	187.53
2005	196.8
2006	205.36
2007	216.82
2008	224.16
2009	232.99
2010	242.29
2011	250.38
2012	258.77
2013	266.02
2014	275
2015	286.78
2016	298.21