Year Percent 1990-01-01 2.4537600000000000 1991-01-01 2.0392400000000000 1992-01-01 1.9779000000000000 1993-01-01 2.6034900000000003 1994-01-01 2.4898900000000000 1995-01-01 2.2718100000000000 1996-01-01 2.2979100000000000 1997-01-01 2.6922700000000000 1998-01-01 2.5699600000000000 1999-01-01 2.4864200000000000 2000-01-01 2.4286500000000000 2001-01-01 2.4303900000000000 2002-01-01 2.2265400000000000 2003-01-01 2.1946800000000000 2004-01-01 2.1413700000000000 2005-01-01 2.1778800000000000 2006-01-01 2.3698900000000003 2007-01-01 2.3741500000000000 2008-01-01 2.4964100000000000 2009-01-01 2.4269000000000000 2010-01-01 2.4070700000000000 2011-01-01 2.4528900000000000 2012-01-01 2.4367900000000002 2013-01-01 2.6105200000000000 2014-01-01 2.7694200000000000 2015-01-01 2.9785100000000000