Year	% of land area
1961	38.494570418182164
1962	38.50414995709375
1963	38.51070437845431
1964	38.52330903491691
1965	38.53540950512102
1966	38.54801416158363
1967	38.56918998444081
1968	38.55557695546119
1969	38.533392760087004
1970	38.46684017396443
1971	38.43961411600519
1972	38.452722958726305
1973	38.46542845244061
1974	38.4169257343725
1975	38.28951786684844
1976	38.32561760295736
1977	38.315130528780465
1978	38.3308611400458
1979	38.30827359566481
1980	38.27550148886202
1981	38.294358054930086
1982	38.314071737637605
1983	38.31961778648115
1984	38.33222244294376
1985	38.34170114460365
1986	38.34593630917508
1987	38.3707422730935
1988	38.36872552805948
1989	38.346541332685284
1990	38.356725895107076
1991	38.34666334575984
1992	38.207597576073496
1993	38.27683527132931
1994	38.35452807768264
1995	38.364636152403236
1996	38.3986683712413
1997	38.40540824347745
1998	38.39134451213321
1999	38.406009566685704
2000	38.46089492149364
2001	38.37856911823926
2002	38.31100892028802
2003	38.354156811833825
2004	38.38710838392281
2005	38.45846379288806
2006	38.446038219747294
2007	38.440148363510296
2008	38.50763727545898
2009	38.56846562118049
2010	38.550949574038505
2011	38.586446260154275
2012	38.568083026579835
2013	38.39610312266981
2014	38.485753353455046
2015	38.411367548334034
2016	38.4854220983614
2017	38.521494353386984
2018	38.5297519697016
2019	38.5258310001142
2020	38.52461431834974
2021	38.52217428372002