Year % 1989 7.82 1993 7.69 1995 6.81 1996 5.52 1997 5.06 1998 3.58 1999 3.32 2000 3.17 2001 3.27 2002 3.31 2003 3.43 2004 3.21 2005 3.17 2006 3.2 2007 3.27 2008 3.22 2009 3.16 2010 2.69 2011 2.65 2012 2.59 2013 2.62 2014 2.59 2015 2.63 2016 2.68 2017 2.71 2018 2.66 2019 4.88 2020 2.63 2021 2.54