Year Percent 1995-01-01 36.2188264062975 1996-01-01 36.3413717371029 1997-01-01 36.9552867399612 1998-01-01 38.7244097660314 1999-01-01 39.3567226811583 2000-01-01 41.3576454969655 2001-01-01 41.6932456500423 2002-01-01 43.8420982761693 2003-01-01 48.0259072171801 2004-01-01 48.9295941002390 2005-01-01 49.4140566692860 2006-01-01 51.2517075194092 2007-01-01 53.2763310789930 2008-01-01 54.2794682826799 2009-01-01 56.0200214904015 2010-01-01 56.4616314553484 2011-01-01 57.0936194353458 2012-01-01 58.2224888485634 2013-01-01 59.4535930192950 2014-01-01 59.2173714788962 2015-01-01 58.9882692925018 2016-01-01 60.3198199809829 2017-01-01 61.0551846022623