Year	Number of
1990	66.92
1991	70.03
1992	73.37
1993	76.99
1994	80.46
1995	83.64
1996	86.49
1997	89.96
1998	92.95
1999	96.99
2000	100.26
2001	103.71
2002	108.19
2003	112.19
2004	116.04
2005	120.06
2006	123.62
2007	127.27
2008	130.97
2009	134.8
2010	138.92
2011	142.24
2012	145.99
2013	149.57
2014	153.47
2015	157.77
2016	162.27