Year % 1988 6.51 1993 6.47 1995 6.16 1996 5.96 1997 4.65 1998 4.28 1999 3.17 2000 3.06 2001 3.43 2002 2.38 2003 1.31 2004 1.27 2005 1.21 2006 1.21 2007 1.17 2008 1.09 2009 0.99 2010 1.12 2011 1.11 2012 1.09 2013 1.02 2014 1.01 2015 0.99 2016 0.98 2017 0.98 2018 0.96 2019 0.87 2020 0.87 2021 0.87