Year % (cumulative) 1975 7.11627006530762 1992 14.8787298202515 2001 16.4798698425293 2006 16.7709808349609 2007 17.1444702148438 2008 17.5093898773193 2009 17.5846900939941 2010 17.4761695861816 2011 17.6929206848145 2012 18.1234703063965 2013 19.2977104187012 2014 20.1537303924561 2015 20.3896903991699 2016 20.5625095367432 2017 20.5775203704834 2018 21.0044002532959 2019 20.9701290130615 2020 22.1183204650879 2021 22.2995719909668 2022 22.1036491394043