Year % 2010 8.65738703548396 2011 8.13171240346954 2012 7.92991262699532 2013 7.73182739633685 2014 7.42400985630468 2015 8.43098711693538 2016 8.74722800678583 2017 9.01864922404764 2018 9.15081252889815 2019 9.07841434175283 2020 9.06900760368607 2021 8.84649373877203 2022 8.59552115400606