Year	Number of
1990	129.87
1991	132.76
1992	136.43
1993	135.51
1994	139.93
1995	137.39
1996	133.77
1997	135.73
1998	131.56
1999	131.86
2000	130.55
2001	129.38
2002	128
2003	121.2
2004	120.72
2005	117.22
2006	118.57
2007	117.23
2008	114.16
2009	112.47
2010	114.96
2011	114.5
2012	120.53
2013	119.58
2014	122.16
2015	122.4
2016	122.49