Year	Number of
1990	101.89
1991	104.25
1992	106.83
1993	109.58
1994	112.53
1995	115.78
1996	117.05
1997	118.55
1998	120.19
1999	122.04
2000	124.2
2001	124.82
2002	125.68
2003	126.72
2004	127.96
2005	129.51
2006	131.74
2007	134.08
2008	136.78
2009	139.74
2010	143.07
2011	146.34
2012	149.99
2013	153.89
2014	158.06
2015	162.49
2016	167.02