Year	% of land area
1961	36.82482371823315
1962	36.93080829722336
1963	37.0162551946389
1964	37.219603597390446
1965	37.511695068674456
1966	37.61210151192834
1967	37.60804468593828
1968	37.60931244406017
1969	37.34080127384336
1970	37.4652951214132
1971	37.44830716257983
1972	37.53071144050284
1973	37.82964880564507
1974	37.76217871839796
1975	37.999274842354275
1976	38.005106529714986
1977	38.07280481342404
1978	38.24699477937205
1979	38.38447047011007
1980	38.73394067399093
1981	38.56236228977401
1982	39.14000360043307
1983	38.670223150784615
1984	39.04048458786451
1985	39.27991338676511
1986	38.99045885237464
1987	39.319431942940746
1988	39.12435946520891
1989	39.41179572866933
1990	39.34550212095934
1991	39.617446380170236
1992	42.4834152291978
1993	42.62641982711467
1994	42.987945630605786
1995	43.56819861902288
1996	43.5524617965519
1997	43.780970712024846
1998	43.9176814964171
1999	44.12268587919998
2000	44.03900971133133
2001	44.2177538613492
2002	44.2147857441789
2003	44.25099780882757
2004	44.182630211312194
2005	44.18440579393806
2006	44.27481038033527
2007	44.231590103457705
2008	44.144502535082125
2009	44.159108110545525
2010	44.219210559602104
2011	44.50839642822161
2012	44.488121522363045
2013	44.539788604806795
2014	44.68472808663673
2015	44.66507319988049
2016	44.83861440176109
2017	44.937469181614205
2018	44.961176237416915
2019	44.86242865532754
2020	45.02042138201258
2021	44.975027499513644