Year Percent 1995-01-01 57.294100000000000 1996-01-01 45.988300000000000 1997-01-01 37.016600000000000 1998-01-01 31.492800000000000 1999-01-01 25.707900000000000 2000-01-01 22.679200000000000 2001-01-01 19.733200000000000 2002-01-01 21.637400000000000 2003-01-01 25.197600000000000 2004-01-01 29.730000000000000 2005-01-01 38.719400000000000 2006-01-01 37.407600000000000 2007-01-01 27.784400000000000 2008-01-01 14.064100000000000 2009-01-01 11.006400000000000 2010-01-01 8.864620000000000 2011-01-01 11.531100000000000 2012-01-01 6.796289999999999 2013-01-01 5.348820000000000 2014-01-01 3.659240000000000 2015-01-01 3.996090000000000 2016-01-01 5.553999999999999