Year % 2006 12 2007 20.4 2008 21.6 2009 21.6 2010 21.6 2011 22 2012 33.2 2013 33.2 2014 34 2015 34 2016 34 2017 34.4 2018 34.4 2019 37.6518218623482 2020 38.8 2021 39.2 2022 36.5546218487395 2023 34.8