Year Percent 1992-01-01 3.5929900000000004 1993-01-01 3.1253900000000003 1994-01-01 3.1253900000000003 1995-01-01 2.9310700000000000 1996-01-01 3.1551500000000000 1997-01-01 3.9579600000000000 1998-01-01 4.5959200000000000 1999-01-01 5.8684800000000000 2000-01-01 7.4491900000000000 2001-01-01 8.7640900000000000 2002-01-01 9.1363600000000000 2003-01-01 9.6142700000000000 2004-01-01 11.0102000000000000 2005-01-01 11.0116000000000000 2006-01-01 11.5993000000000000 2007-01-01 13.7254000000000000 2008-01-01 13.5257000000000000 2009-01-01 12.8897000000000000 2010-01-01 12.9425000000000000 2011-01-01 11.1842000000000000 2012-01-01 10.7641000000000000 2013-01-01 12.1280000000000000 2014-01-01 13.5070000000000000 2015-01-01 15.0236000000000000 2016-01-01 16.7269000000000000