Year Percent 1987-01-01 0.05539600000000000 1988-01-01 0.03670300000000000 1989-01-01 0.03809500000000000 1990-01-01 0.04943800000000000 1991-01-01 0.04628900000000000 1992-01-01 0.04628900000000000 1993-01-01 0.08414600000000000 1994-01-01 0.35524700000000000 1995-01-01 0.33731900000000000 1996-01-01 0.43237100000000000 1997-01-01 0.46613800000000000 1998-01-01 0.52308800000000000 1999-01-01 0.47001600000000000 2000-01-01 0.43318000000000000 2001-01-01 0.44481300000000000 2002-01-01 0.35555900000000000 2003-01-01 0.37197800000000003 2004-01-01 0.35551900000000003 2005-01-01 0.27512700000000000 2006-01-01 0.19953800000000002 2007-01-01 0.15842400000000000 2008-01-01 0.09235000000000000 2009-01-01 0.07230000000000000 2010-01-01 0.07818600000000000 2011-01-01 0.09288800000000000 2012-01-01 0.15710700000000000 2013-01-01 0.15539000000000000 2014-01-01 0.14633600000000000 2015-01-01 0.11148800000000002 2016-01-01 0.13119800000000000