Year % 1990 18.42 1993 19.38 1995 39.94 1996 28.02 1997 23.66 1998 21.72 1999 22.49 2000 22.31 2001 23.7 2002 20.62 2003 24.39 2004 20.38 2005 23.87 2006 29.15 2007 19.78 2008 17.55 2009 16.93 2010 15.36 2011 19.88 2012 19.25 2013 17.99 2014 18.38 2015 17.93 2016 19.67 2017 25.75 2018 25.37 2019 30.47 2020 19.87 2021 19.9