Year	% of land area
1961	38.2529349300254
1962	38.222579041886476
1963	38.22737595992166
1964	38.22822035624533
1965	38.25548577196763
1966	38.26141077343261
1967	38.31993591796306
1968	38.99317087966388
1969	38.89208984417583
1970	38.30004365010892
1971	38.38161870710404
1972	38.35680462515617
1973	38.25700399966229
1974	38.29435539433101
1975	38.27810709541262
1976	38.318498049283846
1977	38.0343589687737
1978	38.09245085802541
1979	37.98051168217337
1980	38.02628822634521
1981	38.01325322433411
1982	37.93759812140073
1983	37.70393462301443
1984	37.91841837323158
1985	38.055499857291444
1986	37.66493817856854
1987	37.74257525940399
1988	37.90414285245123
1989	37.89379996700349
1990	37.93855762988527
1991	37.82750041781419
1992	37.86488981969332
1993	37.84166323147084
1994	38.219265282087264
1995	38.16781027882229
1996	38.289571106261455
1997	38.26160455131276
1998	38.516674800655714
1999	38.38569026333118
2000	38.39500468280141
2001	38.352772662958145
2002	38.020109972187726
2003	37.743134621515644
2004	36.46024791904047
2005	36.87594616776736
2006	36.777164581416265
2007	36.38285507748486
2008	36.079882055538796
2009	35.81503241935908
2010	35.44690899878675
2011	35.891414430358125
2012	35.5309529940874
2013	35.09609585467855
2014	35.14142508511117
2015	34.385907609728875
2016	34.19505507880578
2017	35.021379120292664
2018	34.62119501256239
2019	34.74151555941414
2020	34.45985874397776
2021	34.826857224594