Year Percent 1990-01-01 2.1669400000000003 1991-01-01 2.1621300000000000 1992-01-01 2.1788100000000000 1993-01-01 2.2929800000000000 1994-01-01 2.3049200000000000 1995-01-01 2.3913000000000000 1996-01-01 2.4035700000000000 1997-01-01 2.3238900000000000 1998-01-01 2.2032900000000000 1999-01-01 2.1799700000000000 2000-01-01 2.1530000000000000 2001-01-01 2.2094900000000000 2002-01-01 2.2974300000000000 2003-01-01 2.4870099999999997 2004-01-01 2.4859600000000000 2005-01-01 2.5161500000000000 2006-01-01 2.3672800000000000 2007-01-01 2.3152900000000000 2008-01-01 2.3191599999999997 2009-01-01 2.3860799999999998 2010-01-01 2.2804200000000000 2011-01-01 2.3221800000000000 2012-01-01 2.3139900000000000 2013-01-01 2.2912600000000000 2014-01-01 2.2477300000000000 2015-01-01 2.0135400000000003 2016-01-01 2.0105700000000000