Year Percent 1992-01-01 15.0675000000000000 1993-01-01 12.8196000000000000 1994-01-01 3.4828600000000000 1995-01-01 5.2529999999999990 1996-01-01 6.6781000000000000 1997-01-01 7.1075800000000005 1998-01-01 10.0570000000000000 1999-01-01 12.8027000000000000 2000-01-01 12.1314000000000000 2001-01-01 9.9575900000000000 2002-01-01 8.5594800000000000 2003-01-01 7.0867000000000000 2004-01-01 5.2223700000000000 2005-01-01 3.2293600000000000 2006-01-01 1.8121200000000002 2007-01-01 1.2724799999999998 2008-01-01 1.6794799999999999 2009-01-01 4.3049000000000000 2010-01-01 6.0195500000000000 2011-01-01 6.3307000000000000 2012-01-01 7.4160500000000000 2013-01-01 9.1059900000000000 2014-01-01 14.7925000000000000 2015-01-01 20.9579000000000000 2016-01-01 17.1195000000000000