Year	Number of
1990	100.91
1991	102.5
1992	105.84
1993	107.99
1994	112.82
1995	115.37
1996	118.81
1997	125.17
1998	131.24
1999	137.48
2000	143.74
2001	150.75
2002	160.69
2003	169.55
2004	180.59
2005	189.44
2006	194.14
2007	196.45
2008	197.17
2009	196.59
2010	197.08
2011	197.12
2012	197.64
2013	197.9
2014	197.65
2015	196.37
2016	197.03