Year Percent 1996-01-01 1.8549900000000001 1997-01-01 2.9160200000000000 1998-01-01 5.3902199999999990 1999-01-01 6.3507400000000000 2000-01-01 8.4259200000000000 2001-01-01 8.6734400000000000 2002-01-01 9.0953300000000000 2003-01-01 8.7159300000000000 2004-01-01 7.2997000000000000 2005-01-01 4.3826400000000000 2006-01-01 4.4434000000000000 2007-01-01 6.9762900000000000 2008-01-01 8.4223699999999990 2009-01-01 8.4180100000000000 2010-01-01 6.7820800000000006 2011-01-01 5.0086900000000005 2012-01-01 10.4619000000000000 2013-01-01 17.7297000000000000 2014-01-01 28.3586000000000000 2015-01-01 31.6658000000000000 2016-01-01 30.3194000000000000