Year	Number of
1990	42.04
1991	44.29
1992	46.91
1993	49.61
1994	52.32
1995	56.2
1996	60.48
1997	64.1
1998	66.22
1999	67.78
2000	68.48
2001	69.71
2002	71.58
2003	73.72
2004	75.14
2005	75.76
2006	76.45
2007	76.39
2008	76.85
2009	79.02
2010	81.45
2011	82.32
2012	82.95
2013	83.69
2014	84.19
2015	86.38
2016	88.99