Year	Number of
1990	37.49
1991	40.52
1992	42.81
1993	44.58
1994	48.04
1995	50.54
1996	52.22
1997	54.47
1998	56.97
1999	59.3
2000	62
2001	66.4
2002	68.81
2003	71.25
2004	73.73
2005	77.37
2006	79.96
2007	81.6
2008	82.96
2009	83.52
2010	88.17
2011	91.37
2012	94.37
2013	97.94
2014	102.01
2015	104.27
2016	105.79