Year % (cumulative) 1970 7.3436598777771 2006 28.4451503753662 2007 28.8402538299561 2008 29.7625293731689 2009 30.9062309265137 2010 31.7834396362305 2011 32.2605400085449 2012 32.5986518859863 2013 32.7364387512207 2014 32.8841705322266 2015 32.6591491699219 2016 33.2288017272949 2017 35.6569213867188 2018 35.7474136352539 2019 35.6207695007324 2020 36.7356109619141 2021 39.0090293884277 2022 39.7613945007324