Year Percent 1991-01-01 11.48700046539310 1992-01-01 12.29899978637700 1993-01-01 14.57100009918210 1994-01-01 10.17700004577640 1995-01-01 9.92300033569336 1996-01-01 10.59000015258790 1997-01-01 8.10299968719482 1998-01-01 7.17700004577637 1999-01-01 9.89999961853027 2000-01-01 6.73500013351440 2001-01-01 8.21700000762939 2002-01-01 7.03200006484985 2003-01-01 9.81799983978271 2004-01-01 7.77600002288818 2005-01-01 8.60499954223633 2006-01-01 7.68100023269653 2007-01-01 7.49200010299683 2008-01-01 7.97900009155273 2009-01-01 11.80900001525880 2010-01-01 13.94400024414060 2011-01-01 14.20699977874760 2012-01-01 14.10799980163570 2013-01-01 13.00199985504150 2014-01-01 12.56000041961670 2015-01-01 10.79800033569340 2016-01-01 11.93400001525880 2017-01-01 10.97099971771240