Year % 2010 14.0923292012703 2011 14.4935071240575 2012 12.3072603314702 2013 12.256873226181 2014 13.1762292805739 2015 11.270681093697 2016 11.3988393213787 2017 12.5042459209271 2018 11.9321956834363 2019 12.9361139633731 2020 13.1562152294052 2021 13.3554466445201