Year Percent 1991-01-01 4.67000007629395 1992-01-01 4.01200008392334 1993-01-01 4.06799983978271 1994-01-01 3.73600006103516 1995-01-01 13.41100025177000 1996-01-01 4.03999996185303 1997-01-01 4.01499986648560 1998-01-01 3.96499991416931 1999-01-01 3.92300009727478 2000-01-01 4.46000003814697 2001-01-01 4.25099992752075 2002-01-01 5.67299985885620 2003-01-01 6.64699983596802 2004-01-01 8.86800003051758 2005-01-01 11.26399993896480 2006-01-01 6.70800018310547 2007-01-01 7.76300001144409 2008-01-01 9.19900035858154 2009-01-01 8.79100036621094 2010-01-01 10.04599952697750 2011-01-01 15.23499965667720 2012-01-01 20.59399986267090 2013-01-01 21.02599906921390 2014-01-01 19.72100067138670 2015-01-01 18.45299911499020 2016-01-01 17.69199943542480 2017-01-01 15.96700000762940