Year	% of land area
1961	1.779268974632708
1962	1.779268974632708
1963	1.779268974632708
1964	1.779268974632708
1965	1.779268974632708
1966	1.8046871028417468
1967	1.8046871028417468
1968	1.8046871028417468
1969	1.8046871028417468
1970	1.8301052310507853
1971	1.8301052310507853
1972	1.8301052310507853
1973	1.840272482334401
1974	1.840272482334401
1975	1.8491236982473964
1976	1.8586065532131064
1977	1.8680889001778005
1978	1.8775717551435103
1979	1.8870546101092203
1980	1.896536957073914
1981	1.9060198120396241
1982	1.9155026670053341
1983	1.9249850139700277
1984	1.9344678689357377
1985	1.943950723901448
1986	1.9534330708661416
1987	1.9629159258318516
1988	1.9723987807975616
1989	1.9818811277622554
1990	1.9913639827279654
1991	2.0008468376936754
1992	2.010329184658369
1993	2.0198120396240795
1994	2.029294894589789
1995	2.038777241554483
1996	2.0482600965201927
1997	2.057742951485903
1998	2.0672252984505968
1999	2.0767081534163068
2000	2.0861910083820168
2001	2.095673355346711
2002	2.105156210312421
2003	2.1146390652781304
2004	2.1241214122428245
2005	2.1336042672085345
2006	2.1336042672085345
2007	2.1336042672085345
2008	2.1336042672085345
2009	2.1336042672085345
2010	2.1336042672085345
2011	2.1336042672085345
2012	2.1336042672085345
2013	2.1336042672085345
2014	2.1336042672085345
2015	2.1336042672085345
2016	2.1336042672085345
2017	2.1336042672085345
2018	2.1336042672085345
2019	2.1336042672085345
2020	2.1336042672085345
2021	2.1336042672085345