Year % 2012 9.92742756260372 2013 9.35397224610027 2014 8.64435559021165 2015 8.23684100594144 2016 7.92752471631559 2017 7.87198632346278 2018 8.03811869008349 2019 8.06577613962305 2020 7.82858252049211 2021 7.75674121847486 2022 7.85920663005895 2023 7.73563920961447