Year % 1990 6.52 1993 6.79 1995 4.49 1996 4.24 1997 3.29 1998 3 1999 2.64 2000 2.6 2001 2.56 2002 2.55 2003 2.52 2004 2.5 2005 2.41 2006 2.36 2007 2.26 2008 2.4 2009 2.44 2010 2.14 2011 2.35 2012 2.3 2013 2.25 2014 2.32 2015 2.23 2016 2.28 2017 2.31 2018 2.31 2019 2.14 2020 2.83 2021 2.78