Year	Number of
1990	55.48
1991	57
1992	58.78
1993	61.33
1994	66.06
1995	69.59
1996	72.38
1997	75.33
1998	76.08
1999	79.42
2000	81.88
2001	81.49
2002	82.05
2003	84.76
2004	87.13
2005	90.06
2006	93.12
2007	96.3
2008	99.42
2009	102.3
2010	105.84
2011	108.49
2012	111.84
2013	115.27
2014	118.79
2015	122.77
2016	126.8