Year	Percent
1991-01-01	28.2140007019043
1992-01-01	27.2830009460449
1993-01-01	26.4939994812012
1994-01-01	25.7509994506836
1995-01-01	26.9419994354248
1996-01-01	24.8239994049072
1997-01-01	25.1000003814697
1998-01-01	28.5459995269775
1999-01-01	25.4190006256104
2000-01-01	26.9190006256104
2001-01-01	24.4200000762939
2002-01-01	24.2290000915527
2003-01-01	24.9309997558594
2004-01-01	23.8260002136230
2005-01-01	25.3640003204346
2006-01-01	22.1739997863770
2007-01-01	21.2959995269775
2008-01-01	23.3430004119873
2009-01-01	22.5919990539551
2010-01-01	21.9740009307861
2011-01-01	21.3689994812012
2012-01-01	21.4599990844727
2013-01-01	21.1240005493164
2014-01-01	21.5020008087158
2015-01-01	21.5809993743896
2016-01-01	21.2649993896484
2017-01-01	21.5489997863770