Year	Number of
1990	107.81
1991	109.44
1992	110.69
1993	111.39
1994	111.47
1995	111.3
1996	111.31
1997	111.04
1998	111.57
1999	110.6
2000	112.25
2001	112.78
2002	115.99
2003	120.38
2004	126.81
2005	133.61
2006	140.86
2007	147.82
2008	155.02
2009	161.92
2010	171.59
2011	179.61
2012	187.33
2013	193.8
2014	200.89
2015	207.32
2016	213.76