Year	Number of
1990	64.79
1991	64.45
1992	64.14
1993	63.65
1994	63.06
1995	62.89
1996	61.95
1997	61.1
1998	60.95
1999	62.2
2000	62.47
2001	63.85
2002	65.22
2003	66.64
2004	70.98
2005	72.5
2006	74.14
2007	75.96
2008	77.96
2009	80.97
2010	83.54
2011	85.97
2012	87.87
2013	90.69
2014	92.87
2015	95.02
2016	97.17