Year	% of land area
1961	0.33503502117919565
1962	0.35184853617077755
1963	0.3587111953510151
1964	0.3780638942392849
1965	0.3869853511735936
1966	0.39549504855708817
1967	0.4047596384504088
1968	0.4150536272207651
1969	0.4216417800337931
1970	0.42822993284682115
1971	0.43454357929263965
1972	0.43962194708601543
1973	0.44861203061212657
1974	0.45547468979236405
1975	0.4694058879282462
1976	0.46446477331847524
1977	0.4718764452331317
1978	0.47654305347569326
1979	0.47709206621011224
1980	0.48409197857395453
1981	0.49013111865256354
1982	0.49404283438529895
1983	0.4985035628524533
1984	0.5010427467491412
1985	0.50447407633926
1986	0.5044054497474576
1987	0.508317165480193
1988	0.5100328302752524
1989	0.5141504257833949
1990	0.524787547512763
1991	0.5293855291635221
1992	0.5295227823471269
1993	0.5241012815947392
1994	0.5239640284111345
1995	0.5135327864571735
1996	0.5199150594947943
1997	0.5215620976980514
1998	0.5364540681191667
1999	0.5413951827289378
2000	0.552787196968132
2001	0.5603361220663934
2002	0.56081650820901
2003	0.5763261179563468
2004	0.5734979963733381
2005	0.5752964794227976
2006	0.579406776443238
2007	0.5965921288738398
2008	0.5903913140082625
2009	0.6062049428470224
2010	0.6441496951979254
2011	0.6458185098347625
2012	0.654965993711936
2013	0.6836060693933009
2014	0.7170402410946224
2015	0.7329284079335752
2016	0.7437666038671399
2017	0.7575629968624777
2018	0.7717756545560457
2019	0.7971638156829636
2020	0.8251280337430063
2021	0.8259363818179599