Year	Number of
1990	55.28
1991	56.01
1992	56.86
1993	57.45
1994	58.3
1995	59.42
1996	60.57
1997	61.98
1998	63.3
1999	64.71
2000	66.17
2001	67.5
2002	68.89
2003	71.01
2004	73.07
2005	75.07
2006	76.52
2007	77.96
2008	79.58
2009	81.38
2010	83.46
2011	84.96
2012	86.69
2013	88.51
2014	90.33
2015	92.1
2016	94.03