Year	Number of
1990	129.35
1991	129.87
1992	134.06
1993	133.82
1994	135.03
1995	135.15
1996	135.24
1997	135.35
1998	136.41
1999	139.26
2000	142.73
2001	147.54
2002	151.41
2003	155.16
2004	158.68
2005	162.3
2006	167.19
2007	172.5
2008	177.34
2009	179.3
2010	180.71
2011	181.97
2012	184.06
2013	186.62
2014	191.95
2015	198.24
2016	204.56