Year	Percent
1991-01-01	9.35299968719482
1992-01-01	9.35599994659424
1993-01-01	8.44099998474121
1994-01-01	7.52500009536743
1995-01-01	5.73000001907349
1996-01-01	5.73199987411499
1997-01-01	5.73400020599365
1998-01-01	5.71600008010864
1999-01-01	5.57999992370605
2000-01-01	5.44799995422363
2001-01-01	5.34299993515015
2002-01-01	5.22499990463257
2003-01-01	5.11399984359741
2004-01-01	5.01499986648560
2005-01-01	4.90500020980835
2006-01-01	4.79099988937378
2007-01-01	4.67899990081787
2008-01-01	4.56899976730347
2009-01-01	4.46000003814697
2010-01-01	4.33900022506714
2011-01-01	4.20499992370605
2012-01-01	4.14900016784668
2013-01-01	4.03299999237061
2014-01-01	3.91799998283386
2015-01-01	3.80399990081787
2016-01-01	3.71399998664856
2017-01-01	3.69799995422363