Year	% of land area
1961	5.5187747035573125
1962	5.526185770750988
1963	5.533596837944664
1964	5.54100790513834
1965	5.479249011857707
1966	5.513833992094861
1967	5.513833992094861
1968	5.5187747035573125
1969	5.526185770750988
1970	5.508893280632411
1971	5.533596837944664
1972	5.536067193675888
1973	5.570652173913044
1974	5.575345849802371
1975	5.571195732701141
1976	5.4557260334864415
1977	5.345195090630711
1978	5.242072899688844
1979	5.107341087568528
1980	4.986311720390268
1981	4.8641472150179075
1982	4.702214894405334
1983	4.525462022971471
1984	4.5406940842287264
1985	4.5534560948499445
1986	4.5738750154378165
1987	4.6043225886130665
1988	4.615454365814499
1989	4.636466098555021
1990	4.6646412251451155
1991	4.685406199827097
1992	4.703700876867976
1993	4.791404223786588
1994	4.77981153513647
1995	4.767477584290478
1996	4.7647770779300975
1997	4.742810176608621
1998	4.718125972582438
1999	4.731480795356305
2000	4.731052735581079
2001	4.722078053600099
2002	4.684698036309745
2003	4.70116512288502
2004	4.6752211930344565
2005	4.6380140792886255
2006	4.636062739286156
2007	4.621514141039891
2008	4.586488823020872
2009	4.616129430653328
2010	4.560306286278869
2011	4.563270347042114
2012	4.544744967271829
2013	4.5657403976781525
2014	4.574632579967889
2015	4.591675929356552
2016	4.589205878720514
2017	4.586735828084476
2018	4.586735828084476
2019	4.591675929356552
2020	4.596616030628628
2021	4.599086081264666