Year	Number of
1990	113.35
1991	113.97
1992	114.63
1993	115.79
1994	117
1995	119.26
1996	114.93
1997	110.01
1998	106.16
1999	99.83
2000	97.62
2001	92.01
2002	90.5
2003	90.31
2004	92.22
2005	94.59
2006	97.17
2007	100.19
2008	102.93
2009	105.73
2010	111.15
2011	117.39
2012	123.67
2013	129.4
2014	135.76
2015	142.28
2016	149.03