Year	Number of
1990	95.31
1991	95.18
1992	94.52
1993	93.2
1994	95.55
1995	97.86
1996	101.65
1997	105.41
1998	106.29
1999	109.82
2000	111.73
2001	114.25
2002	118.12
2003	120.11
2004	123.94
2005	128.08
2006	130.94
2007	130.91
2008	130.79
2009	131.03
2010	128.81
2011	126.46
2012	125.27
2013	124.68
2014	124.45
2015	124.32
2016	123.93