Year	Percent
1991-01-01	6.34299993515015
1992-01-01	12.23299980163570
1993-01-01	18.36199951171880
1994-01-01	21.65099906921390
1995-01-01	23.25200080871580
1996-01-01	25.66699981689450
1997-01-01	23.48100090026860
1998-01-01	26.52199935913090
1999-01-01	23.88500022888180
2000-01-01	20.48999977111820
2001-01-01	17.04500007629390
2002-01-01	18.93899917602540
2003-01-01	19.45499992370610
2004-01-01	19.97800064086910
2005-01-01	20.98200035095210
2006-01-01	17.89900016784670
2007-01-01	16.22800064086910
2008-01-01	15.59099960327150
2009-01-01	18.18799972534180
2010-01-01	20.32600021362300
2011-01-01	22.71299934387210
2012-01-01	24.74500083923340
2013-01-01	21.61800003051760
2014-01-01	23.13500022888180
2015-01-01	18.97100067138670
2016-01-01	17.74300003051760
2017-01-01	19.75499916076660