Year	% of land area
1961	3.4288865871211613
1962	3.432922153916518
1963	3.465206688279369
1964	3.498836411574006
1965	3.502871978369362
1966	3.5755121806857777
1967	3.594344825730774
1968	3.6387360604796943
1969	3.6777465395014732
1970	3.7167570185232512
1971	3.8902863907235767
1972	3.903738280041432
1973	3.9171901693592868
1974	3.9548554594492793
1975	3.9346776254724976
1976	3.9050834689732175
1977	3.875489312473937
1978	3.6616042723200475
1979	3.102005676697292
1980	3.136980588923714
1981	3.212311169103701
1982	3.2876417492836865
1983	3.3629723294636733
1984	3.4383029096436597
1985	3.5136334898236457
1986	3.5876188810718466
1987	3.6629494612518325
1988	3.7382800414318194
1989	3.8889412017917917
1990	3.8889412017917917
1991	3.7059955070689674
1992	3.7382800414318194
1993	3.7396252303636044
1994	3.8337884555885875
1995	3.825717321997875
1996	3.825717321997875
1997	3.825717321997875
1998	3.825717321997875
1999	3.825717321997875
2000	3.825717321997875
2001	3.6616042723200475
2002	3.4732778218700813
2003	3.8660729899514386
2004	3.8499307227700132
2005	3.6683302169789744
2006	4.053054251469619
2007	3.9669621598353486
2008	4.105516619809252
2009	4.775420707838416
2010	4.573642368070596
2011	4.842680154427689
2012	5.111717940784783
2013	4.977199047606237
2014	4.977199047606237
2015	4.977199047606237
2016	4.977199047606237
2017	5.111717940784783
2018	5.111717940784783
2019	5.111717940784783
2020	5.111717940784783
2021	5.111717940784783