Year	% of land area
1961	35.2633678515752
1962	35.31300212027031
1963	35.40549328763791
1964	35.467685624316125
1965	35.51428004322168
1966	35.53979484801274
1967	35.55913028601847
1968	35.63866471657811
1969	35.685009967468126
1970	35.71311611962078
1971	35.80236810278639
1972	35.84253398689107
1973	35.87383945636323
1974	35.877101107568926
1975	35.95112444290663
1976	35.9958618519573
1977	36.01948392156855
1978	36.10161297371905
1979	36.12802583636454
1980	36.18583512064524
1981	36.25266464669731
1982	36.3000582926895
1983	36.37645625200183
1984	36.42883345698374
1985	36.68159956894208
1986	36.9102950909801
1987	37.02521596128293
1988	37.26537366899729
1989	37.40461430716993
1990	37.49023135225733
1991	37.642730250766206
1992	37.8707231009538
1993	38.31135053878416
1994	38.57366445676723
1995	38.84514232447584
1996	38.98597424175686
1997	39.13957726245688
1998	39.28752754812433
1999	39.484158040313524
2000	39.638460818701624
2001	39.81093719481364
2002	39.92366950214313
2003	40.19076434395411
2004	40.19358448712715
2005	40.56963299432811
2006	40.70497625763063
2007	40.851885969645785
2008	40.9678784753795
2009	41.18317854337883
2010	41.37403191993357
2011	41.56661258639691
2012	41.59925347576982
2013	41.82355308590354
2014	41.963546663519104
2015	42.10325544136652
2016	42.209870669601635
2017	42.32613412855916
2018	42.470411496035794
2019	42.531210303218
2020	42.595286807601184
2021	42.63856879379631