Year Percent 1999-01-01 5.74308 2000-01-01 7.41902 2001-01-01 7.66408 2002-01-01 9.88681 2003-01-01 12.72880 2004-01-01 16.92690 2005-01-01 17.29370 2006-01-01 18.07140 2007-01-01 16.77830 2008-01-01 11.65750 2009-01-01 18.17100 2010-01-01 20.52820 2011-01-01 19.15380 2012-01-01 26.80720 2013-01-01 25.49390 2014-01-01 22.87160 2015-01-01 24.32140 2016-01-01 23.27410