Year	Number of
1990	52.01
1991	53.59
1992	55.25
1993	57.02
1994	58.92
1995	61
1996	63.12
1997	65.43
1998	67.98
1999	70.75
2000	73.82
2001	75.62
2002	77.64
2003	79.83
2004	82.14
2005	84.61
2006	87.41
2007	90.29
2008	93.38
2009	96.71
2010	100.37
2011	103.71
2012	107.35
2013	111.19
2014	115.29
2015	119.64
2016	124.29