Year	% of land area
1990	27.233594486431297
1991	27.110764042412
1992	26.672701120000617
1993	26.55213697176123
1994	26.43157282352184
1995	26.311008675282455
1996	26.190444531997
1997	26.069880383757607
1998	25.94931623551822
1999	25.828752087278836
2000	25.70818794399338
2001	25.598916604011766
2002	25.489657891442473
2003	25.380625392015
2004	25.086871866175482
2005	24.978366214594455
2006	24.869717747591352
2007	24.761150859218287
2008	24.652989946533367
2009	24.548170173014626
2010	24.439766037012802
2011	24.312457073116462
2012	24.038852711971746
2013	23.912739838219924
2014	23.786358119299383
2015	23.659824472467143
2016	23.528667832007038
2017	23.402518422888853
2018	23.27930481470303
2019	23.15377206170985
2020	23.03147870147413
2021	22.907003011822628