Year	Number of
1990	116.3
1991	113.22
1992	113.88
1993	115.09
1994	115.9
1995	118.75
1996	119.93
1997	122.68
1998	126.65
1999	132.56
2000	138.62
2001	146.04
2002	151.88
2003	160.59
2004	168.4
2005	177.93
2006	187.87
2007	198.39
2008	209.01
2009	221.83
2010	236.22
2011	245.24
2012	254.97
2013	264.95
2014	275.18
2015	286.29
2016	296.68