Year	% of land area
1992	39.12029341287886
1993	39.03423167632673
1994	38.948975127094094
1995	38.86235849195361
1996	38.773935710699185
1997	38.68471631558915
1998	38.6143166731441
1999	38.52073597011559
2000	38.39080555731135
2001	38.34796732807824
2002	38.3061286700775
2003	38.26262186411318
2004	38.21895580416021
2005	38.17541808096875
2006	38.12553573591599
2007	38.08311593156774
2008	38.04114605549955
2009	38.000731769114026
2010	37.95815626498218
2011	37.928985676236074
2012	37.900240370230314
2013	37.87313510593378
2014	37.84433016656076
2015	37.81537619302699
2016	37.81091955412142
2017	37.766193293614506
2018	37.75133446851206
2019	37.732839370340706
2020	37.71750094855252
2021	37.68854655717787