Year	% of land area
1961	22.809215290962833
1962	23.44927479496565
1963	24.38881168157529
1964	24.839006439742413
1965	25.328348568184932
1966	25.856838066902853
1967	26.346180195345376
1968	26.815948638650198
1969	27.24656971167962
1970	27.888586584196208
1971	28.18414922977549
1972	29.81072246471843
1973	31.474485701423006
1974	33.046252617980386
1975	33.70588580712091
1976	34.34790267963749
1977	35.16412534987962
1978	35.96860380903913
1979	36.60670594452818
1980	37.068644913777916
1981	37.85746442482726
1982	38.714791833858555
1983	38.9477186869972
1984	39.24719606960402
1985	40.27677190784709
1986	40.66433087357357
1987	41.57450723247666
1988	41.75067039871597
1989	41.76437197831236
1990	41.85441092994578
1991	42.1147409422772
1992	41.83679461332185
1993	41.584294075045506
1994	41.766329346826126
1995	41.948364618606746
1996	42.130399890387366
1997	42.312435162167986
1998	42.49251306543483
1999	42.67454833721545
2000	42.85658360899607
2001	43.03861888077669
2002	43.2206541525573
2003	43.40268942433792
2004	43.584724696118535
2005	43.766759967899155
2006	43.948795239679775
2007	44.128873142946624
2008	44.31090841472724
2009	44.49294368650786
2010	44.67497895828848
2011	44.682808432343556
2012	44.69063790639864
2013	44.698986866057275
2014	44.710211591536336
2015	44.71804106559142
2016	44.710211591536336
2017	44.71999843410519
2018	44.71744700424749
2019	45.01947581671201
2020	45.551683728395545
2021	45.998160073597056