Year	Number of
1990	103.1
1991	105.06
1992	109.37
1993	111.97
1994	118.23
1995	121.26
1996	125.3
1997	132.46
1998	139.03
1999	144.42
2000	149.14
2001	153.97
2002	161.14
2003	166.87
2004	175.01
2005	180.73
2006	185.09
2007	187.97
2008	189.23
2009	189.5
2010	191.11
2011	192.65
2012	194.21
2013	195.55
2014	195.61
2015	194.33
2016	194.25