Year % of land area 2006 12.936802973977695 2007 12.936802973977695 2008 12.862453531598513 2009 12.862453531598513 2010 12.788104089219331 2011 12.862453531598513 2012 12.788104089219331 2013 0.5799256505576209 2014 0.6490706319702602 2015 0.6468401486988847 2016 0.6691449814126395 2017 0.6840148698884758 2018 0.6840148698884758 2019 0.6691449814126395 2020 0.6765799256505577 2021 0.6617100371747212