Year % 1991 8.032128 1992 20.82973 1994 24.47803 1995 26.08333 1996 28.83699 1997 28.53427 1998 31.56095 1999 30.66911 2000 30.41592 2001 29.60623 2002 30.64899 2003 30.73952 2004 26.19735 2005 27.04128 2006 22.97228 2007 35.57013 2008 36.18102 2009 35.97963 2010 24.53062 2011 23.72953 2012 3.731268 2013 26.22934 2014 25.40811 2015 5.237727 2016 3.344934 2017 16.14715 2018 2.809233 2019 2.87014 2020 2.505915 2021 2.692791