Year Percent 1996 3.51848 1997 10.06577 1998 7.53093 1999 3.45764 2000 6.42783 2001 7.84516 2002 8.35465 2003 9.48365 2004 9.5243 2005 11.89968 2006 12.92044 2007 10.88057 2008 -2.52864 2009 -12.97671 2010 -1.92043 2011 8.33571 2012 5.33307 2013 3.53281 2014 2.82202 2015 3.81812 2016 3.14717 2017 5.56195