Year	% of land area
2006	2.186142236450949
2007	2.1712782986508117
2008	2.1769951978047106
2009	2.164418019666133
2010	2.1735650583123713
2011	2.1564143608506745
2012	2.1415504230505373
2013	2.1461239423736567
2014	2.143837182712097
2015	2.28675966155957
2016	2.3324948547907614
2017	2.378230048021953
2018	2.3439286530985592
2019	2.355362451406357
2020	2.4616482340349624
2021	2.425972172672137