Year % 1990 54.226211709025925 1991 52.50062089343022 1992 50.90051097965608 1993 47.082187344162925 1994 46.21538653892177 1995 45.470699833356356 1996 45.09840398527674 1997 44.558680819972544 1998 43.74579317255844 1999 42.44416004285502 2000 42.04729382788661 2001 41.23530584568196 2002 40.30151047254227 2003 39.45965809898654 2004 38.65682529971418 2005 38.13918468095331 2006 37.279094103454426 2007 36.57577911455633 2008 35.68741971270654 2009 34.870438990984105 2010 34.62842628702368 2011 34.13894463371942 2012 33.55801990429336 2013 33.19965929540874 2014 33.232385419662904 2015 32.76968298281086 2016 32.73417933942576 2017 32.524700756337324 2018 32.50521288560369 2019 32.37773276067028 2020 32.457774352449576 2021 32.44821329773852 2022 32.37700606963361