Year % 1986 47.4 1990 43.6 1994 43 1998 44.1 2005 43.6 2006 44.8 2009 42.1 2011 34.7 2012 34.4 2013 34 2014 34.8 2015 35.3 2016 35.9 2017 36.7 2018 37.4 2019 36.5 2020 35.8 2021 35.5 2022 34.8