Year Percent 2003-01-01 17.48646927 2004-01-01 20.34427071 2005-01-01 15.48867989 2006-01-01 19.44944000 2007-01-01 23.10718918 2008-01-01 25.55409050 2009-01-01 28.61495018 2010-01-01 31.92097092 2011-01-01 29.12254906 2012-01-01 27.74451256