Year	% of land area
1961	1.2787027968222875
1962	1.305909239307868
1963	1.3113505278049842
1964	1.3276743932963324
1965	1.398411143758842
1966	1.398411143758842
1967	1.3820872782674938
1968	1.5453259331809772
1969	1.4147350092501905
1970	1.4038524322559582
1971	1.4201762977473065
1972	1.577973664163674
1973	1.7847426270540863
1974	1.8772445315050603
1975	1.909892262487757
1976	2.24181086081184
1977	2.317988899771466
1978	2.3887256502339755
1979	2.4812275546849496
1980	2.470344977690717
1981	2.633583632604201
1982	2.791380999020568
1983	2.8566764609859616
1984	2.9927086734138646
1985	3.1831537708129285
1986	3.3409511372292955
1987	3.536837523125476
1988	3.7544890630101206
1989	3.8361083904668627
1990	4.031994776363042
1991	4.200674719773642
1992	4.2877353357275005
1993	3.5640439656110563
1994	3.6728697355533786
1995	3.8252258134726302
1996	3.9775818913918815
1997	4.080966372837088
1998	4.2169985852649905
1999	4.35847208619001
2000	4.407443682664055
2001	4.434650125149635
2002	4.505386875612145
2003	4.646222561141674
2004	4.733888979680776
2005	4.831944217464727
2006	4.993737406741817
2007	5.156828577651928
2008	5.265737312132433
2009	5.412764103681115
2010	5.4947448673963954
2011	5.739802864455699
2012	5.805151663671514
2013	5.832380330011436
2014	5.832380330011436
2015	5.805151663671514
2016	5.805151663671514
2017	5.805151663671514
2018	5.805151663671514
2019	5.805151663671514
2020	5.805151663671514
2021	5.805151663671514