Year	Number of
1990	97.91
1991	96.64
1992	94.91
1993	93.22
1994	92.17
1995	92.2
1996	93.83
1997	97.07
1998	101.55
1999	106.4
2000	111.34
2001	115.32
2002	119.47
2003	123.96
2004	128.86
2005	134.43
2006	139.91
2007	145.76
2008	152.48
2009	159.76
2010	167.75
2011	175.29
2012	183.57
2013	192.23
2014	200.97
2015	209.63
2016	217.6