Year	Number of
1990	100.33
1991	99.96
1992	101.17
1993	102.78
1994	104.64
1995	107.39
1996	111.28
1997	113.82
1998	120.32
1999	124.58
2000	128.3
2001	127.58
2002	128.61
2003	133.26
2004	139.56
2005	146.53
2006	154.52
2007	161.14
2008	166.5
2009	172.21
2010	176.77
2011	181.94
2012	191.32
2013	200.46
2014	210.57
2015	220.36
2016	229.21