Year % 1996 53.19893 1997 48.24133 1998 53.19893 1999 53.19893 2000 68.71495 2001 51.98292 2002 47.56949 2003 48.44994 2004 47.99601 2005 51.67586 2006 46.66424 2007 40.45135 2008 43.79072 2010 42.60777 2011 51.63193 2012 51.13345 2013 51.49044 2015 41.19784 2016 37.69824 2017 36.42838 2018 36.17597 2020 35.50867 2021 31.64557