Year Percent 1990-01-01 1.3240299999999998 1991-01-01 1.4696100000000000 1992-01-01 1.6139000000000000 1993-01-01 1.7254200000000002 1994-01-01 1.8914900000000001 1995-01-01 2.0496100000000000 1996-01-01 2.0728200000000000 1997-01-01 2.1142300000000000 1998-01-01 2.2030500000000000 1999-01-01 2.2806500000000000 2000-01-01 2.5277500000000000 2001-01-01 3.4079099999999998 2002-01-01 2.9145300000000000 2003-01-01 3.1488300000000000 2004-01-01 3.3803400000000003 2005-01-01 2.8459100000000000 2006-01-01 3.0800600000000000 2007-01-01 2.9855500000000000 2008-01-01 2.9437700000000000 2009-01-01 3.0636300000000000 2010-01-01 2.9684100000000000 2011-01-01 2.7656200000000000 2012-01-01 2.7922100000000000 2013-01-01 2.8365500000000000 2014-01-01 2.8209600000000000 2015-01-01 2.8452800000000000 2016-01-01 2.8364100000000000