Year	% of land area
1990	26.26820475267799
1991	26.25530260213326
1992	26.238399630691788
1993	26.221496659250313
1994	26.20459368370364
1995	26.18770146285519
1996	26.170916669356135
1997	26.15401361054079
1998	26.13711055583068
1999	26.120207497015336
2000	26.048425558045256
2001	26.116580501221396
2002	26.18558114771762
2003	26.24676275657275
2004	26.315591327773962
2005	26.381097647468938
2006	26.446176464541757
2007	26.51478204476923
2008	26.583114594730578
2009	26.651528125637274
2010	26.719469913325078
2011	26.77084375817152
2012	26.822016231136434
2013	26.87380045744684
2014	26.924736282313432
2015	26.976046160267412
2016	27.086679501885314
2017	27.086059059772786
2018	27.116707264035316
2019	27.148011008032963
2020	27.179847379479835
2021	27.194736788610328