Year Percent 1996-01-01 2.8000800000000000 1997-01-01 24.9425000000000000 1998-01-01 12.8353000000000000 1999-01-01 4.0135100000000000 2000-01-01 6.7532500000000000 2001-01-01 3.7811000000000000 2002-01-01 9.2121600000000000 2003-01-01 9.0380000000000000 2004-01-01 10.3879000000000000 2005-01-01 25.7150000000000000 2006-01-01 31.0422000000000000 2007-01-01 9.0025000000000000 2008-01-01 16.4361000000000000 2009-01-01 9.3895800000000000 2010-01-01 14.8292000000000000 2011-01-01 4.6851199999999995 2012-01-01 4.4889500000000000 2013-01-01 1.5972899999999999 2014-01-01 5.6108800000000000 2015-01-01 4.4741000000000000 2016-01-01 7.7750200000000000 2017-01-01 5.2097500000000000