Year	Number of
1990	90.74
1991	92.4
1992	92.47
1993	91.97
1994	92.44
1995	94.78
1996	96.09
1997	99.52
1998	106.76
1999	112.74
2000	116.44
2001	114.72
2002	112.19
2003	107.39
2004	103.7
2005	101.47
2006	104.99
2007	109.11
2008	112.87
2009	116.17
2010	119.03
2011	122.94
2012	127
2013	132.57
2014	139.22
2015	147.13
2016	155.64