Year Percent 1998-01-01 16.200000000000000 1999-01-01 15.500000000000000 2000-01-01 12.600000000000000 2001-01-01 13.300000000000000 2002-01-01 12.100000000000000 2003-01-01 10.500000000000000 2004-01-01 9.900000000000000 2005-01-01 8.600000000000000 2006-01-01 8.400000000000000 2007-01-01 8.600000000000000 2008-01-01 8.200000000000000 2009-01-01 8.700000000000000 2010-01-01 9.282080000000000 2011-01-01 8.924610000000001 2012-01-01 9.883830000000000 2013-01-01 11.258400000000000 2014-01-01 11.595400000000000 2015-01-01 10.754000000000001 2016-01-01 10.826100000000000