Year Percent 1991-01-01 4.16699981689453 1992-01-01 4.28700017929077 1993-01-01 4.46899986267090 1994-01-01 4.34299993515015 1995-01-01 6.86999988555908 1996-01-01 6.64599990844727 1997-01-01 5.20399999618530 1998-01-01 10.48499965667720 1999-01-01 14.19299983978270 2000-01-01 11.09200000762940 2001-01-01 11.24499988555910 2002-01-01 14.86100006103520 2003-01-01 14.88399982452390 2004-01-01 12.11400032043460 2005-01-01 10.72999954223630 2006-01-01 10.41499996185300 2007-01-01 8.98999977111816 2008-01-01 8.52799987792969 2009-01-01 12.53400039672850 2010-01-01 12.17399978637700 2011-01-01 9.32800006866455 2012-01-01 9.25399971008301 2013-01-01 9.43700027465820 2014-01-01 9.18999958038330 2015-01-01 10.46800041198730 2016-01-01 9.88199996948242 2017-01-01 8.66100025177002