Year Number 2009 1.51885330677032 2010 1.64520108699799 2011 1.94000649452209 2012 1.93440723419189 2013 1.93195283412933 2014 1.9245411157608 2015 1.94708216190338 2016 1.9642106294632 2017 1.92758142948151 2018 1.9365086555481 2019 1.8871865272522 2020 1.91047644615173 2021 1.87737047672272 2022 1.56596922874451