Year	% of land area
1990	24.688238993710694
1991	23.821443396226417
1992	22.95464779874214
1993	22.08785220125786
1994	21.221056603773587
1995	20.35426100628931
1996	19.487465408805033
1997	18.620669811320756
1998	17.75387421383648
1999	16.887078616352202
2000	16.020283018867925
2001	15.665292452830187
2002	15.310301886792455
2003	14.955311320754717
2004	14.60032075471698
2005	14.245330188679246
2006	13.890339622641509
2007	13.535349056603774
2008	13.180358490566038
2009	12.825367924528303
2010	12.470377358490566
2011	12.115389937106919
2012	11.760402515723271
2013	11.405415094339624
2014	11.050427672955975
2015	10.695440251572327
2016	10.340440251572327
2017	9.985440251572328
2018	9.630440251572328
2019	9.275471698113208
2020	8.920471698113207
2021	8.565492767295598