Year	Percent
1991-01-01	74.5550003051758
1992-01-01	74.6060028076172
1993-01-01	74.5199966430664
1994-01-01	74.4229965209961
1995-01-01	74.4100036621094
1996-01-01	74.8600006103516
1997-01-01	75.4380035400391
1998-01-01	75.9000015258789
1999-01-01	76.5390014648438
2000-01-01	77.1149978637695
2001-01-01	77.6289978027344
2002-01-01	77.3899993896484
2003-01-01	77.1240005493164
2004-01-01	76.9150009155273
2005-01-01	76.5739974975586
2006-01-01	76.7630004882813
2007-01-01	77.2170028686523
2008-01-01	77.6129989624023
2009-01-01	78.0910034179688
2010-01-01	78.4729995727539
2011-01-01	78.8929977416992
2012-01-01	78.8160018920898
2013-01-01	78.8069992065430
2014-01-01	78.7490005493164
2015-01-01	78.7180023193359
2016-01-01	78.6490020751953
2017-01-01	78.6190032958984