Year Percent 1990-01-01 0.5679310000000001 1991-01-01 0.5732740000000000 1992-01-01 0.6405820000000000 1993-01-01 0.6486510000000000 1994-01-01 0.7624330000000000 1995-01-01 0.7386640000000000 1996-01-01 0.8818469999999999 1997-01-01 1.1548300000000000 1998-01-01 1.0866600000000000 1999-01-01 1.5035900000000000 2000-01-01 1.9783900000000000 2001-01-01 2.0488600000000000 2002-01-01 2.1091400000000000 2003-01-01 2.4995700000000003 2004-01-01 2.9799100000000000 2005-01-01 2.6889300000000000 2006-01-01 3.1878599999999997 2007-01-01 3.9554300000000002 2008-01-01 3.0476900000000002 2009-01-01 3.2471300000000000 2010-01-01 3.4840600000000000 2011-01-01 3.1251900000000004 2012-01-01 2.4670900000000002 2013-01-01 2.6857900000000003 2014-01-01 2.8359900000000002 2015-01-01 3.3287699999999996 2016-01-01 3.1717800000000000