Year Percent 2000-01-01 3.6050000000000000 2001-01-01 3.7350000000000000 2002-01-01 3.9019999999999997 2003-01-01 3.9019999999999997 2004-01-01 3.9019999999999997 2005-01-01 3.9019999999999997 2006-01-01 3.9019999999999997 2007-01-01 3.9019999999999997 2008-01-01 3.9019999999999997 2009-01-01 3.9019999999999997 2010-01-01 3.9019999999999997 2011-01-01 3.9019999999999997 2012-01-01 3.9019999999999997 2013-01-01 6.6400000000000000 2014-01-01 8.4200000000000000 2015-01-01 9.7300000000000000 2016-01-01 8.7000000000000000