Year Percent 1991-01-01 9.71899986267090 1992-01-01 8.35999965667725 1993-01-01 8.44999980926514 1994-01-01 9.44900035858154 1995-01-01 9.88300037384033 1996-01-01 12.68500041961670 1997-01-01 13.38799953460690 1998-01-01 13.66100025177000 1999-01-01 14.31700038909910 2000-01-01 13.70699977874760 2001-01-01 14.21700000762940 2002-01-01 20.07699966430660 2003-01-01 16.63899993896480 2004-01-01 15.24499988555910 2005-01-01 14.48499965667720 2006-01-01 14.56299972534180 2007-01-01 14.83399963378910 2008-01-01 15.41600036621090 2009-01-01 16.76899909973140 2010-01-01 16.51799964904790 2011-01-01 16.44400024414060 2012-01-01 17.45499992370610 2013-01-01 13.39099979400630 2014-01-01 13.98600006103520 2015-01-01 15.04100036621090 2016-01-01 15.59300041198730 2017-01-01 15.74400043487550