Year	Number of
1990	119.07
1991	117.66
1992	117.71
1993	118.46
1994	118.78
1995	119.86
1996	120.03
1997	120.62
1998	124.36
1999	129.18
2000	133.16
2001	137.62
2002	144.32
2003	151.96
2004	156.39
2005	157.67
2006	159.42
2007	163.7
2008	170.79
2009	176.81
2010	182.66
2011	186.11
2012	188.58
2013	191.05
2014	194.93
2015	199.88
2016	204.51