Year	Number of
1990	69.72
1991	71.16
1992	71.47
1993	77.46
1994	80
1995	82.14
1996	85.05
1997	86.57
1998	89.08
1999	91.57
2000	93.17
2001	94.82
2002	97.18
2003	99.09
2004	101.07
2005	103.36
2006	105.38
2007	106.6
2008	107.74
2009	109.68
2010	113.3
2011	115.27
2012	116.11
2013	117.69
2014	118.49
2015	119.8
2016	121.34