Year	Number of
1990	105.39
1991	106.68
1992	107.97
1993	109.08
1994	110.11
1995	111.22
1996	111.52
1997	111.96
1998	112.71
1999	113.82
2000	115.49
2001	117.07
2002	119.41
2003	122.56
2004	126.1
2005	130
2006	134.75
2007	139.7
2008	145.11
2009	150.95
2010	157.38
2011	162.48
2012	168.17
2013	173.92
2014	180.04
2015	186.53
2016	193.41