Year	% of land area
2006	40.44134461468099
2007	40.851817973930935
2008	41.20283558198034
2009	40.22410244683284
2010	40.26526412074091
2011	40.34072718957238
2012	39.59067002058084
2013	39.91767665218385
2014	40.09147038646238
2015	39.80105190944432
2016	39.51520695174937
2017	39.09215641436085
2018	39.60667733821175
2019	39.56094214498056
2020	41.40801522178618
2021	41.44369128314901