Year	Number of
1990	99.56
1991	100.19
1992	99.41
1993	99.06
1994	99.41
1995	96.93
1996	95.27
1997	97.89
1998	98.09
1999	97.38
2000	100.16
2001	102.17
2002	105.47
2003	110.25
2004	109.39
2005	114.02
2006	115.31
2007	122.79
2008	126.77
2009	130.07
2010	134.61
2011	140.7
2012	146.57
2013	153.22
2014	159.66
2015	165.04
2016	172.04