Year	Number of
1990	109.16
1991	114.65
1992	120.6
1993	127.09
1994	134.02
1995	141.45
1996	148.41
1997	155.68
1998	163.58
1999	171.88
2000	180.65
2001	185.82
2002	191.52
2003	198.37
2004	206.2
2005	215.16
2006	229.22
2007	244.78
2008	260.38
2009	275.08
2010	287.91
2011	296.8
2012	302.37
2013	304.55
2014	308
2015	314.98
2016	328.02