Year % 1996 12.12 1997 12.56 2000 9.94 2001 9.95 2002 11 2008 10.1 2009 10.18 2010 9 2011 8.93 2012 9.04 2013 8.84 2014 8.07 2015 7.52 2016 6.79 2017 6.42 2018 7.07 2019 9.53 2020 6.51 2021 6.85