Year	Percent
1991-01-01	9.08600044250488
1992-01-01	9.07199954986572
1993-01-01	10.28699970245360
1994-01-01	11.50300025939940
1995-01-01	12.72900009155270
1996-01-01	13.95199966430660
1997-01-01	15.17300033569340
1998-01-01	16.14599990844730
1999-01-01	19.94700050354000
2000-01-01	16.26199913024900
2001-01-01	14.75899982452390
2002-01-01	13.25199985504150
2003-01-01	11.74600028991700
2004-01-01	10.23099994659420
2005-01-01	8.70800018310547
2006-01-01	7.19600009918213
2007-01-01	8.06099987030029
2008-01-01	8.98600006103516
2009-01-01	9.82400035858154
2010-01-01	10.62100028991700
2011-01-01	8.99499988555908
2012-01-01	7.36899995803833
2013-01-01	4.55900001525879
2014-01-01	4.51300001144409
2015-01-01	4.51100015640259
2016-01-01	4.71799993515015
2017-01-01	4.90100002288818