Year % 2013 12.9868868262001 2014 12.265792482412 2015 11.3588840793988 2016 10.055842933819 2017 8.42948949057021 2018 7.97371472046651 2019 8.58202379960379 2020 9.18579121790452 2021 7.88790949084099 2022 7.30732740429232