Year	Number of
1990	9.06
1991	10.15
1992	10.38
1993	10.69
1994	10.41
1995	10.1
1996	10.34
1997	10.38
1998	11.2
1999	11.29
2000	11.25
2001	11.15
2002	11.25
2003	11.17
2004	10.68
2005	11.1
2006	10.95
2007	10.61
2008	10.14
2009	10.73
2010	10.11
2011	9.45
2012	10.43
2013	10.84
2014	11.02
2015	11.24
2016	11.41