Year	%
1991	98.71138
1992	99.26582
1993	99.18984
1994	98.27366
1995	99.51661
1996	99.79966
1997	98.86743
1998	100.0567
1999	100.0636
2000	100.064
2001	100.0302
2002	100.1291
2003	100.0993
2004	100.0848
2005	99.98469
2006	99.64718
2007	99.633
2008	99.76133
2009	99.71711
2010	99.63226
2011	99.66149
2012	99.33214
2013	99.50065
2014	99.64976
2015	99.73507
2016	99.75937
2017	99.76506