Year	Number of
1990	126.24
1991	126.6
1992	126.75
1993	126.71
1994	126.77
1995	127.1
1996	127.4
1997	127.92
1998	128.52
1999	128.97
2000	129.27
2001	132.88
2002	136.27
2003	139.88
2004	143.21
2005	146.36
2006	147.07
2007	147.92
2008	148.84
2009	150.38
2010	152.65
2011	158.04
2012	163.75
2013	169.69
2014	175.86
2015	182.58
2016	189.41