Year	Number of
1990	85.08
1991	84.04
1992	81.89
1993	79.41
1994	76.58
1995	75.24
1996	73.77
1997	74.81
1998	73.7
1999	74.55
2000	75.75
2001	79.66
2002	85.24
2003	90.56
2004	94.97
2005	100.47
2006	103.84
2007	106.81
2008	109.39
2009	111.28
2010	113.39
2011	116.16
2012	118.59
2013	121.22
2014	123.74
2015	126.74
2016	130.45