Year	Percent
1991-01-01	81.5989990234375
1992-01-01	81.5579986572266
1993-01-01	81.5149993896484
1994-01-01	81.4899978637695
1995-01-01	81.4690017700195
1996-01-01	81.5009994506836
1997-01-01	81.5319976806641
1998-01-01	81.5690002441406
1999-01-01	81.5979995727539
2000-01-01	81.6200027465820
2001-01-01	82.0439987182617
2002-01-01	82.4410018920898
2003-01-01	82.7850036621094
2004-01-01	83.6989974975586
2005-01-01	84.6399993896484
2006-01-01	84.9609985351563
2007-01-01	85.2220001220703
2008-01-01	85.4209976196289
2009-01-01	85.5699996948242
2010-01-01	85.6320037841797
2011-01-01	86.7399978637695
2012-01-01	87.8170013427734
2013-01-01	87.0559997558594
2014-01-01	86.2070007324219
2015-01-01	84.9789962768555
2016-01-01	84.7890014648438
2017-01-01	84.9250030517578