Year	% of land area
1990	12.863714925694907
1991	12.796991986670028
1992	12.730269047645148
1993	12.663546108620269
1994	12.596823169595387
1995	12.530100230570508
1996	12.463377291545626
1997	12.396654352520747
1998	12.329931413495865
1999	12.263208474470986
2000	12.196485535446104
2001	12.080871417661482
2002	11.965257299876859
2003	11.849643182092235
2004	11.734029064307611
2005	11.61841494652299
2006	11.502800828738366
2007	11.387186710953744
2008	11.27157259316912
2009	11.155958475384498
2010	11.040344357599874
2011	10.958712897697584
2012	10.877081437795292
2013	10.795449977893004
2014	10.713818517990711
2015	10.63218705808842
2016	10.600396829746884
2017	10.559836883242165
2018	10.520373151507844
2019	10.48017860992659
2020	10.440714878192269
2021	10.400763952073492