Year % 1996 34.06 1999 31.17 2000 31.95 2001 37.39 2002 37.03 2003 37.08 2004 27.9 2006 23.62 2007 26.36 2010 23.29 2011 22.98 2012 17.4 2013 25.99 2020 19.21 2021 18.98