Year	Number of
1990	119.28
1991	120.19
1992	121.06
1993	122.35
1994	123.46
1995	123.13
1996	122.66
1997	122.45
1998	122.64
1999	124.24
2000	127.05
2001	126.89
2002	130.74
2003	137.79
2004	144.44
2005	146.19
2006	149.02
2007	151.4
2008	149.04
2009	152.36
2010	151.1
2011	154.56
2012	161.49
2013	167.58
2014	172.79
2015	179.59
2016	183.88