Year Percent 2000-01-01 16.10611608239660 2001-01-01 18.24322211653970 2002-01-01 19.93271684088140 2003-01-01 19.61964051957800 2004-01-01 18.97837409926570 2005-01-01 17.75268703260570 2006-01-01 13.84889329381710 2007-01-01 9.60760523854493 2008-01-01 7.12099462420450 2009-01-01 8.16637164298252 2010-01-01 9.64034635503099 2011-01-01 9.63281523586770 2012-01-01 10.08882080186310 2013-01-01 10.32861949665930 2014-01-01 8.99087202737545 2015-01-01 7.50308016151202 2016-01-01 6.16170316787172 2017-01-01 4.88723888573846