Year Percent 2002 -26.41064 2003 -28.73596 2004 -24.34535 2005 -21.13414 2006 -25.46879 2007 -33.92 2008 -36.78857 2009 -37.66994 2010 -38.26353 2011 -41.01055 2012 -39.10367 2013 -40.34102 2014 -40.42669 2015 -35.24662 2016 -31.76247