Year	Number of
1990	127.6
1991	129.15
1992	132.44
1993	137.22
1994	139.03
1995	141.25
1996	140.17
1997	139.59
1998	140.34
1999	142.72
2000	144.96
2001	151.57
2002	158.35
2003	165.06
2004	172.45
2005	175.06
2006	177.48
2007	180.22
2008	183.23
2009	186.18
2010	188.61
2011	190.04
2012	191.27
2013	192.59
2014	194.19
2015	195.94
2016	197.13