Year % 1988 5.56 1993 5.69 1995 5.43 1996 4.61 1997 2.88 1998 2.46 1999 2.12 2000 1.79 2001 1.7 2002 1.42 2003 0.76 2004 0.69 2005 0.59 2006 0.55 2007 0.49 2008 0.47 2009 0.5 2010 0.66 2011 0.66 2012 0.63 2013 0.65 2014 0.66 2015 0.66 2016 0.7 2017 0.7 2018 0.7 2019 0.65 2020 0.69 2021 0.68