Year Percent 1995-01-01 41.6932033237422 1996-01-01 41.7126327445410 1997-01-01 40.2887528563027 1998-01-01 41.1123121254028 1999-01-01 39.6152359787486 2000-01-01 39.3076150521766 2001-01-01 39.0866529678268 2002-01-01 36.8321799360697 2003-01-01 34.6204858696860 2004-01-01 34.0711482829263 2005-01-01 33.3235565583816 2006-01-01 33.8295622181612 2007-01-01 33.0201901120926 2008-01-01 33.1757413981974 2009-01-01 32.7385076328389 2010-01-01 32.0356123029206 2011-01-01 31.9108889947076 2012-01-01 31.4691206695589 2013-01-01 30.5973502993798 2014-01-01 30.3394836975869 2015-01-01 29.2812504022117 2016-01-01 28.5916129587892 2017-01-01 28.9541329951337