Year Percent 1990-01-01 3.5289699999999997 1991-01-01 4.4529600000000000 1992-01-01 4.9434900000000000 1993-01-01 5.7614300000000010 1994-01-01 5.7381400000000005 1995-01-01 5.3126300000000000 1996-01-01 4.7011100000000000 1997-01-01 4.2287500000000000 1998-01-01 4.0642900000000000 1999-01-01 3.6031100000000000 2000-01-01 3.8028500000000000 2001-01-01 4.1650199999999990 2002-01-01 4.5666900000000000 2003-01-01 4.3837100000000000 2004-01-01 4.3280100000000000 2005-01-01 4.4026700000000000 2006-01-01 4.6218800000000000 2007-01-01 4.5774099999999995 2008-01-01 4.4009199999999990 2009-01-01 2.7206500000000000 2010-01-01 4.6052100000000000 2011-01-01 4.8180100000000000 2012-01-01 4.7818700000000000 2013-01-01 4.6653100000000000 2014-01-01 5.3338700000000000 2015-01-01 4.9382600000000000