Year Percent 1990-01-01 25.3328000000000000 1991-01-01 21.0701000000000000 1992-01-01 26.9318000000000000 1993-01-01 50.8812000000000000 1994-01-01 47.8896000000000000 1995-01-01 39.8802000000000000 1996-01-01 32.6007000000000000 1997-01-01 25.5257000000000000 1998-01-01 21.4671000000000000 1999-01-01 23.8068000000000000 2000-01-01 20.3055000000000000 2001-01-01 7.5191899999999990 2002-01-01 9.0604900000000000 2003-01-01 7.5360900000000000 2004-01-01 6.4661700000000000 2005-01-01 8.0123600000000010 2006-01-01 12.7745000000000000 2007-01-01 14.5611000000000000 2008-01-01 6.4692300000000005 2009-01-01 5.4571900000000000 2010-01-01 4.4324900000000005 2011-01-01 5.4722599999999995 2012-01-01 5.6004900000000000 2013-01-01 3.4842100000000000 2014-01-01 4.1166500000000000 2015-01-01 2.2743599999999997 2016-01-01 4.0178800000000000 2017-01-01 6.8838500000000000