Year	% of land area
1961	17.413584637268848
1962	17.413584637268848
1963	17.413584637268848
1964	17.413584637268848
1965	17.413584637268848
1966	17.413584637268848
1967	17.769203413940257
1968	17.769203413940257
1969	17.769203413940257
1970	17.769203413940257
1971	17.769203413940257
1972	17.769203413940257
1973	17.94701280227596
1974	18.124822190611663
1975	18.124822190611663
1976	18.124822190611663
1977	18.160384068278805
1978	18.160384068278805
1979	18.195945945945947
1980	18.302631578947366
1981	18.551564722617353
1982	19.013869132290186
1983	19.369487908961595
1984	20.329658605974394
1985	20.61415362731152
1986	19.440611664295876
1987	19.26280227596017
1988	18.907183499288763
1989	20.222972972972972
1990	20.57859174964438
1991	20.713015647226175
1992	20.713015647226175
1993	21.42425320056899
1994	21.779871977240397
1995	22.080192034139404
1996	22.38051209103841
1997	22.68083214793741
1998	22.981152204836416
1999	23.28147226173542
2000	23.581792318634424
2001	23.882112375533428
2002	24.18243243243243
2003	24.482752489331435
2004	24.783072546230443
2005	25.083392603129447
2006	25.38371266002845
2007	25.68403271692745
2008	25.98435277382646
2009	26.284672830725462
2010	26.584992887624466
2011	26.885277382645807
2012	27.18556187766714
2013	27.485846372688478
2014	27.78613086770981
2015	28.086415362731152
2016	28.38655761024182
2017	28.68669985775249
2018	28.986842105263154
2019	28.986842105263154
2020	28.986842105263154
2021	28.986842105263154