Year	Percent
1991-01-01	2.74699997901917
1992-01-01	2.74099993705750
1993-01-01	2.73499989509583
1994-01-01	2.77900004386902
1995-01-01	2.78099989891052
1996-01-01	2.73900008201599
1997-01-01	2.75600004196167
1998-01-01	2.73799991607666
1999-01-01	2.74900007247925
2000-01-01	2.73799991607666
2001-01-01	2.73600006103516
2002-01-01	2.73600006103516
2003-01-01	2.75200009346008
2004-01-01	2.74399995803833
2005-01-01	2.74099993705750
2006-01-01	2.74799990653992
2007-01-01	2.74900007247925
2008-01-01	2.75500011444092
2009-01-01	2.76300001144409
2010-01-01	2.76999998092651
2011-01-01	2.77699995040894
2012-01-01	2.77999997138977
2013-01-01	2.77999997138977
2014-01-01	2.77699995040894
2015-01-01	2.77600002288818
2016-01-01	2.78299999237061
2017-01-01	2.78999996185303