Year	% of land area
1961	34.547063061165865
1962	34.68922447888163
1963	34.80849583159782
1964	34.93305383078414
1965	35.08791432225697
1966	35.24951731609172
1967	35.395689911787535
1968	35.57381539500315
1969	35.735955564581104
1970	35.926328455418684
1971	36.17334299039222
1972	36.42730154337754
1973	36.66281272584471
1974	36.91703333442087
1975	37.10203616388725
1976	37.06150877006966
1977	37.34117200581967
1978	37.605470141778085
1979	37.84042610361593
1980	38.017050049210205
1981	38.11709309584054
1982	38.364029480767485
1983	38.68559913045261
1984	39.02136566667856
1985	39.38910140081836
1986	39.56060548493218
1987	39.77344462393158
1988	39.91852739028338
1989	40.07285825927165
1990	40.258867408485735
1991	40.36780961974121
1992	36.31270238681205
1993	36.28553778256858
1994	36.326057890731086
1995	36.23151865285425
1996	36.220422486540784
1997	36.41316478842291
1998	36.45513187813546
1999	36.486863657085316
2000	36.47876545217219
2001	36.4523026162771
2002	36.467676031357044
2003	36.24454293490202
2004	36.28011514680101
2005	36.043911558855385
2006	36.05753561430175
2007	36.06482354785643
2008	35.97217892770434
2009	35.95404402971494
2010	36.051027821260696
2011	36.029770484488886
2012	36.02329511882395
2013	36.03146877298887
2014	35.95915791840018
2015	35.97991643180468
2016	35.95744853536369
2017	35.9446848197539
2018	35.9190718031324
2019	35.88797439878811
2020	35.923716409714665
2021	35.917662587009