Year Percent 1987-01-01 9.87469609126636 1988-01-01 7.41276595744663 1989-01-01 6.04547975596240 1990-01-01 6.12671846981461 1991-01-01 6.35736412278236 1992-01-01 3.63407691798491 1993-01-01 3.01481859989799 1994-01-01 5.31374007936500 1995-01-01 10.29781179472050 1996-01-01 2.37712902953223 1997-01-01 5.30560105668805 1998-01-01 8.40223795613228 1999-01-01 6.10669589841958 2000-01-01 2.20825620937533 2001-01-01 2.00717374213844 2002-01-01 3.33256493271908 2003-01-01 5.66870773441478 2004-01-01 7.58753638504689 2005-01-01 7.04661816222038 2006-01-01 6.76526117054758 2007-01-01 9.10698496905383 2008-01-01 8.90194489465155 2009-01-01 5.42347236174680 2010-01-01 8.12667639169919 2011-01-01 11.33291519683600 2012-01-01 6.21818236968360 2013-01-01 7.52997282337094 2014-01-01 6.99116532700683 2015-01-01 6.19428022984985 2016-01-01 5.43093776295698 2017-01-01 5.78487050920603