Year % 1988 5.87 1989 6.23 1990 6.78 1991 6.57 1992 6.61 1993 5.52 1994 5.55 1995 13.06 1996 11.09 1997 9.61 1998 9.21 1999 9.51 2000 7.93 2001 9.87 2002 6.42 2003 6.54 2004 6.85 2005 7.36 2006 7.24 2007 6.51 2008 5.94 2009 6.25 2010 6.3 2011 5.84 2012 5.6 2013 5.38 2014 5.72 2015 5.69 2016 5.32 2017 5.16 2018 5.24 2019 5.87 2020 2.21 2021 4.81