Year	Number of
1990	100.88
1991	104.66
1992	105.66
1993	107.78
1994	107.78
1995	108.22
1996	109.74
1997	108.18
1998	101.49
1999	105.91
2000	107.89
2001	107.4
2002	107.31
2003	108.24
2004	108.79
2005	111.86
2006	115.46
2007	118.97
2008	119.56
2009	116.74
2010	119.82
2011	121.28
2012	124.51
2013	126.25
2014	129.5
2015	131.4
2016	133.31