Year	Number of
1990	73.88
1991	78.23
1992	83.34
1993	88.91
1994	94.82
1995	100.87
1996	106.18
1997	111.28
1998	116.3
1999	121.46
2000	127.05
2001	133.37
2002	140.45
2003	148.83
2004	158.64
2005	170.15
2006	177.74
2007	186.6
2008	197.01
2009	207.97
2010	219.24
2011	230.79
2012	242.67
2013	254.86
2014	267.24
2015	279.77
2016	292.04