Year Percent 1997-01-01 8.3592400000000000 1998-01-01 7.4749300000000005 1999-01-01 8.2380600000000000 2000-01-01 7.9763399999999995 2001-01-01 8.0449200000000000 2002-01-01 8.0789700000000000 2003-01-01 7.9129000000000000 2004-01-01 9.0753399999999990 2005-01-01 10.0255000000000000 2006-01-01 8.6134600000000000 2007-01-01 9.1876900000000000 2008-01-01 6.4083500000000000 2009-01-01 8.3993100000000000 2010-01-01 8.8615800000000000 2011-01-01 7.7390500000000000 2012-01-01 7.6687000000000000 2013-01-01 7.1488200000000000 2014-01-01 8.2345399999999990 2015-01-01 9.8433500000000000 2016-01-01 10.5120000000000000