Year	Number of
1990	108.77
1991	112.28
1992	116.1
1993	120.28
1994	124.65
1995	129.27
1996	133.53
1997	137.89
1998	142.68
1999	147.64
2000	152.89
2001	155.99
2002	159.54
2003	164.02
2004	169.16
2005	175.1
2006	180.13
2007	185.69
2008	190.75
2009	194.68
2010	196.97
2011	199.11
2012	199.1
2013	196.85
2014	195.46
2015	196.27
2016	199.87