Year	Number of
1990	9.97
1991	10.19
1992	10.25
1993	10.09
1994	9.95
1995	10.09
1996	9.99
1997	10.03
1998	10.47
1999	10.99
2000	11.98
2001	12.41
2002	13.02
2003	13.08
2004	13.26
2005	13.56
2006	13.51
2007	13.5
2008	13.52
2009	13.6
2010	13.66
2011	13.59
2012	13.72
2013	13.9
2014	14.02
2015	14.04
2016	14.24