Year	Number of
1990	69.9
1991	72.71
1992	74.43
1993	76.16
1994	78.65
1995	80.84
1996	83.43
1997	85.07
1998	87.47
1999	90.21
2000	92.19
2001	94.16
2002	96.86
2003	98.88
2004	100.99
2005	103.37
2006	105.83
2007	107.62
2008	109.33
2009	111.07
2010	115.41
2011	118.5
2012	120.83
2013	122.68
2014	124.2
2015	126.09
2016	128.46