Year Percent 1995-01-01 53.3420163171105 1996-01-01 53.6413776088420 1997-01-01 55.1820468118839 1998-01-01 54.7893165048522 1999-01-01 56.5360440448945 2000-01-01 57.3792892151494 2001-01-01 57.2875264846108 2002-01-01 58.9984720224473 2003-01-01 60.9086017868770 2004-01-01 61.8976695180881 2005-01-01 63.0747144113428 2006-01-01 62.6408454549803 2007-01-01 63.4858192602022 2008-01-01 62.9697959485387 2009-01-01 61.8209274834095 2010-01-01 62.9133276271434 2011-01-01 63.1908279382824 2012-01-01 63.9970183865253 2013-01-01 64.6575150039018 2014-01-01 64.9578564478386 2015-01-01 66.0343174096650 2016-01-01 66.4190798266502 2017-01-01 66.5936631081091