Year Percent 2000-01-01 1.187 2001-01-01 7.350 2002-01-01 8.090 2003-01-01 11.500 2004-01-01 9.820 2005-01-01 10.180 2006-01-01 12.390 2007-01-01 15.720 2008-01-01 13.940 2009-01-01 17.350 2010-01-01 17.320 2011-01-01 16.960 2012-01-01 18.810 2013-01-01 19.900 2014-01-01 24.690 2015-01-01 25.420