Year per 1,000 1990 18.046094714866392 1991 17.926945282326866 1992 18.11797172821242 1993 18.674300589697975 1994 27.350861887937864 1995 18.065230788374834 1996 18.17392152373133 1997 17.68441522166529 1998 17.30333987884008 1999 17.163085788364498 2000 16.407017363121746 2001 15.93145828915504 2002 15.451096947737064 2003 15.028989848718913 2004 14.577009807890736 2005 14.143570058951603 2006 13.722684735112493 2007 13.304041754397588 2008 13.061367081864207 2009 12.6238180307764 2010 12.299682481832681 2011 12.037278644502983 2012 11.789898709293844 2013 11.5698080438222 2014 11.327976217190129 2015 11.080101035184734 2016 10.841346763325241 2017 10.598641133310661 2018 10.3689928164056 2019 10.1225371219343 2020 9.912448698111612 2021 9.706832118806574 2022 9.533830917688833