Year	% of land area
1961	66.34888504358615
1962	66.15299226223513
1963	65.89833164647882
1964	65.72202814326292
1965	65.12129028045317
1966	65.12455516014235
1967	64.70665055992687
1968	64.56952561298117
1969	63.8512520813608
1970	63.80554376571224
1971	63.69127297659082
1972	63.24398445917267
1973	63.097064873159425
1974	62.87178817460577
1975	62.76404714486271
1976	62.68242515263312
1977	62.551829965065785
1978	62.39511573998499
1979	62.18942831956642
1980	62.055568252309904
1981	61.73887492245911
1982	61.676842208364626
1983	61.63766365209442
1984	61.83355643344542
1985	61.75193444121584
1986	61.63766365209442
1987	61.60501485520259
1988	61.445035750432595
1989	61.40259231447322
1990	61.35688399882464
1991	61.2262888112573
1992	61.19364001436547
1993	61.102223383068335
1994	61.076104345554874
1995	60.79858957197427
1996	60.31538737797513
1997	60.259884423259
1998	60.21417610761044
1999	60.18805707009697
2000	60.11622971693493
2001	58.07567991119528
2002	55.17320186751118
2003	52.79845872518286
2004	53.29873012764013
2005	51.92439526001371
2006	52.092582919822405
2007	50.49947767041003
2008	50.93372510610512
2009	50.99582081755256
2010	47.17578686169518
2011	48.261110929693366
2012	47.44628045196264
2013	47.05920773325495
2014	47.108004833600056
2015	46.93490969659362
2016	46.94470753453738
2017	47.23211078088768
2018	47.39850409902996
2019	47.44372937832805
2020	48.12661287688237
2021	47.368376347598826