Year % 1988 13.38 1991 12 1993 10.31 1996 6.51 1997 10.2 1998 6.99 1999 7.29 2000 6.28 2001 7.61 2002 2.43 2003 6.62 2004 7.55 2005 2.24 2006 4.17 2007 5.66 2008 5.48 2009 6.21 2010 5.2 2011 3.85 2012 4.04 2013 4.62 2014 2.01 2016 3.52 2020 3.04 2021 3.15