Year % 2007 33.572 2008 36.57 2009 39.412 2010 34.623 2011 32.799 2012 29.067 2013 32.678 2014 31.465 2015 30.904 2016 30.889 2017 30.258 2018 29.791 2019 33.572 2020 32.599 2021 34.242 2022 39.51