Year % 1997 34.92265 1999 35.07677 2000 25.77699 2001 25.73777 2002 25.40126 2003 25.61795 2004 26.62263 2005 26.41018 2006 15.69174 2007 25.65032 2008 25.4813 2009 15.10838 2010 24.47912 2012 15.80403 2013 15.80682 2018 8.819514 2019 10.33167 2020 10.06113 2021 9.742276