Year % 1996 31.66029 1997 34.78753 1998 31.66029 1999 31.66029 2000 54.98217 2001 32.44298 2002 34.3158 2003 34.72948 2004 34.74808 2005 34.10371 2006 31.01136 2007 28.14805 2008 29.35386 2010 28.63282 2011 33.83272 2012 34.51998 2013 34.20402 2015 28.57312 2016 27.09089 2017 22.24644 2018 22.21086 2020 21.69278 2021 20.09816