Year	Number of
1990	105.16
1991	104.95
1992	105.62
1993	107.91
1994	113.5
1995	115.25
1996	118.48
1997	123.31
1998	129.79
1999	139.66
2000	151.65
2001	168.83
2002	183.06
2003	199.86
2004	204.24
2005	209.31
2006	215.22
2007	220.58
2008	225.67
2009	228.16
2010	230.96
2011	236.25
2012	243.26
2013	252.1
2014	260.93
2015	270.42
2016	274.87