Year % 2010 2.14098016078258 2011 1.64499555407419 2012 1.45359977173878 2013 1.48473224456689 2014 1.50237950472032 2015 1.49992861153731 2016 1.5769576006293 2017 1.7024307788589 2018 1.73167776169038 2019 1.86600368568285 2020 1.50757622452981 2021 1.54166114935143