Year	Number of
1990	98.03
1991	100.78
1992	103.65
1993	106.98
1994	109.59
1995	113.68
1996	119.21
1997	123.21
1998	123.78
1999	123.74
2000	125.99
2001	124.14
2002	127.27
2003	130.44
2004	132.92
2005	136.85
2006	140.86
2007	144.39
2008	154.67
2009	150.53
2010	152.69
2011	151.27
2012	154.15
2013	156.58
2014	159.47
2015	162.17
2016	164.89