Year	Number of
1990	60.32
1991	59.39
1992	58.32
1993	60.71
1994	64.08
1995	67.23
1996	70.77
1997	70.5
1998	71.26
1999	70.74
2000	69.2
2001	66.55
2002	63.91
2003	63.59
2004	63.95
2005	64.42
2006	64.23
2007	64.85
2008	65.8
2009	65.25
2010	65.7
2011	65.35
2012	64.72
2013	65.04
2014	65.45
2015	66.18
2016	66.71