Year	Number of
1990	59.96
1991	62.4
1992	65.18
1993	68.19
1994	71.5
1995	75.11
1996	77.73
1997	80.4
1998	83.19
1999	85.9
2000	88.57
2001	89.76
2002	90.97
2003	92.48
2004	94.21
2005	96.27
2006	98.37
2007	100.7
2008	103.37
2009	106.33
2010	109.63
2011	112.27
2012	115.27
2013	118.42
2014	122.09
2015	126.31
2016	130.47