Year	Number of
1990	45.09
1991	46.85
1992	48.62
1993	50.33
1994	52.1
1995	54.11
1996	55.74
1997	57.34
1998	59.22
1999	61.11
2000	62.71
2001	65.01
2002	67.61
2003	69.73
2004	72.31
2005	75.03
2006	77.81
2007	80.71
2008	83.53
2009	86.34
2010	89.13
2011	91.98
2012	94.78
2013	97.43
2014	100.52
2015	103.6
2016	106.87