Year Percent 2000-01-01 5.57514978731687 2001-01-01 5.01318986435507 2002-01-01 5.13210590403958 2003-01-01 4.96674336685037 2004-01-01 4.69094765484938 2005-01-01 4.74925986822703 2006-01-01 5.34878935064746 2007-01-01 5.26247819409392 2008-01-01 5.61257995156886 2009-01-01 7.53672261023311 2010-01-01 7.78664830215475 2011-01-01 8.03633523962114 2012-01-01 7.88616059644404 2013-01-01 7.52588948434741 2014-01-01 6.11135133983609 2015-01-01 5.30193431054949 2016-01-01 4.81341889055992 2017-01-01 4.33513828069665