Year	Number of
1990	98.44
1991	101.24
1992	104.79
1993	107.44
1994	110.45
1995	115.01
1996	118.81
1997	122.59
1998	126.74
1999	131.08
2000	135.31
2001	139.52
2002	144.27
2003	149.94
2004	155.58
2005	161.32
2006	166.53
2007	171.93
2008	178.1
2009	184.71
2010	191.49
2011	197.69
2012	203.94
2013	210.29
2014	217.03
2015	224
2016	230.98