Year % 1982 10.184890795448 1983 10.4529142374335 1984 11.2123139897257 1985 10.7656082530832 1986 10.9889611214044 1987 11.2569845633899 1988 11.2569845633899 1989 11.2569845633899 1990 11.2569845633899 1991 11.2163014829248 1992 11.5231698453901 1993 11.9238245391238 1994 11.6104913178287 1995 11.5007436413857 1996 11.4303325301194 1997 11.1730597100209 1998 11.2725600466202 1999 11.3956730721677 2000 11.6808005322677 2001 11.1397494990693 2002 10.9728957217648 2003 11.5007049422952 2004 8.94144093203256 2005 9.91817590459821 2006 9.50240122157026 2007 9.16801247233374 2008 9.06404638816547 2009 10.0192940627616 2010 9.45501398850831 2011 8.84037965492994 2012 9.04298186920945 2013 9.07396001934442 2014 8.93663314196025 2015 8.66866666666666 2016 8.2775 2017 8.075 2018 7.81221991666667 2019 7.53996066666667 2020 6.89907858333333 2021 6.29791625 2022 6.53699175 2023 5.935577