Year % 1988 3.21 1993 3.05 1995 49.17 1996 45.18 1997 46.05 1998 49.77 1999 45.36 2000 49.51 2001 44.94 2002 47.85 2003 46.71 2004 46.35 2005 48.32 2006 47.61 2007 46.2 2008 41.1 2009 39.43 2010 42.32 2011 42.17 2012 41.89 2013 41.12 2014 40.28 2015 38.53 2016 36.32 2017 35.23 2018 34.14 2019 34.97 2020 41.79 2021 31.9