Year	% of land area
1961	4.400036699633984
1962	4.392643326768375
1963	4.405381306524785
1964	4.431124496382147
1965	4.463103060945443
1966	4.445644011768825
1967	4.463726598416037
1968	4.449385236592385
1969	4.4619450627857695
1970	4.480651186903575
1971	4.539798169828447
1972	4.637426322367091
1973	4.700509431928618
1974	4.6866134044999965
1975	4.636730229115206
1976	4.628446058917374
1977	4.577137649950162
1978	4.525651086785145
1979	4.604395242213993
1980	4.395865753685787
1981	4.470833040121216
1982	4.533342003504293
1983	4.534357482431769
1984	4.594539751991541
1985	4.63697964499213
1986	4.682141734135146
1987	4.74228659131338
1988	4.76313063245631
1989	4.755897572025515
1990	4.782300024139894
1991	4.973655447999907
1992	5.06776350072375
1993	5.158372564302416
1994	5.102281670192629
1995	5.095729446609509
1996	5.0784937534795676
1997	4.996365945885759
1998	5.007524106446944
1999	4.943823609843002
2000	4.78033386927959
2001	4.832265351297183
2002	4.854559902015366
2003	4.907836571480491
2004	4.855971534091212
2005	4.824871562354413
2006	4.851500944671049
2007	4.8734400395505135
2008	4.66423125984308
2009	4.628186908893275
2010	4.628013794452817
2011	4.626576049656586
2012	4.641533966223109
2013	4.625514623033293
2014	4.612824712859515
2015	4.625606683995425
2016	4.6738917478100115
2017	4.762819444510068
2018	4.763972919172331
2019	4.700134036390679
2020	4.803663056466961
2021	4.7712547019653355