Year % 1990 33.89 1993 36.02 1995 40.03 1996 34.28 1997 29.63 1998 27.75 1999 28.71 2000 28.37 2001 28.92 2002 25.19 2003 28.55 2004 23.86 2005 27.49 2006 26.76 2007 23.3 2008 21.04 2009 20.21 2010 16.19 2011 22.3 2012 22.19 2013 21.58 2014 21.85 2015 21.93 2016 23.03 2017 26.3 2018 26.18 2019 28.84 2020 25.27 2021 25.46