Year	% of land area
1961	27.398907103825138
1962	27.3551912568306
1963	27.311475409836067
1964	27.267759562841533
1965	27.224043715846996
1966	27.180327868852462
1967	27.136612021857925
1968	27.09289617486339
1969	27.049180327868854
1970	27.00546448087432
1971	26.961748633879782
1972	26.91803278688524
1973	26.86338797814208
1974	26.80874316939891
1975	26.754098360655735
1976	26.699453551912566
1977	26.644808743169403
1978	26.59016393442623
1979	26.53551912568306
1980	26.48087431693989
1981	26.42622950819672
1982	26.371584699453553
1983	26.316939890710383
1984	26.262295081967213
1985	26.207650273224044
1986	26.15300546448087
1987	26.098360655737707
1988	26.043715846994537
1989	25.989071038251367
1990	25.61748633879781
1991	25.23497267759563
1992	24.863387978142075
1993	24.48087431693989
1994	24.043715846994534
1995	23.530054644808743
1996	21.85792349726776
1997	20.56830601092896
1998	19.65573770491803
1999	18.743169398907103
2000	19.12863387978142
2001	17.79846994535519
2002	17.881420765027322
2003	16.988196721311475
2004	16.204699453551914
2005	14.27200174920739
2006	13.575379905980103
2007	12.553296162676286
2008	13.340002186509237
2009	13.112566874112893
2010	12.529424609673544
2011	12.30232558139535
2012	12.270116824980894
2013	12.428442926820749
2014	11.987585911778318
2015	11.680071960666162
2016	10.722379417852183
2017	10.56760612888295
2018	10.48452168863039
2019	10.891940012400989
2020	10.620631271450655
2021	10.536841634135904