Year % 1988 13.95 1989 10.61 1990 9.54 1992 8.53 1995 6.84 1996 15.02 1997 13.45 1998 13.61 1999 5.9 2000 9.55 2001 10.41 2002 9.98 2003 9.7 2004 9.25 2005 7.95 2006 7.43 2007 7.13 2008 8.26 2009 7.8 2010 7.19 2011 7.32 2012 7.59 2013 7.85 2014 6.1 2015 5.72 2016 8.67 2017 5.05 2018 4.83 2020 5.48 2021 4.85