Year	Percent
1991-01-01	22.09499931335450
1992-01-01	22.61100006103520
1993-01-01	20.67700004577640
1994-01-01	16.64599990844730
1995-01-01	14.92099952697750
1996-01-01	13.54100036621090
1997-01-01	15.01500034332280
1998-01-01	16.94700050354000
1999-01-01	16.69799995422360
2000-01-01	17.27199935913090
2001-01-01	18.64200019836430
2002-01-01	20.76099967956540
2003-01-01	22.34000015258790
2004-01-01	20.61100006103520
2005-01-01	17.83600044250490
2006-01-01	18.42000007629390
2007-01-01	16.27199935913090
2008-01-01	12.50199985504150
2009-01-01	14.73400020599370
2010-01-01	14.26799964904790
2011-01-01	11.85999965667720
2012-01-01	12.18000030517580
2013-01-01	10.57100009918210
2014-01-01	10.61800003051760
2015-01-01	9.31799983978271
2016-01-01	8.64200019836426
2017-01-01	7.28299999237061