Year	% of land area
1961	43.527302322032604
1962	43.54129047025611
1963	43.55400696864111
1964	43.56418016734912
1965	43.576896665734125
1966	43.58452656476513
1967	43.61758946056614
1968	43.74475444441618
1969	43.87700602762023
1970	43.98509626389278
1971	43.98509626389278
1972	44.00925761082428
1973	44.07538340242631
1974	44.07538340242631
1975	44.10081639919632
1976	44.10081639919632
1977	44.10081639919632
1978	44.10081639919632
1979	44.10081639919632
1980	44.10081639919632
1981	44.164398891121344
1982	44.26613087820137
1983	44.26613087820137
1984	44.393295862051424
1985	44.45687835397645
1986	44.520460845901475
1987	44.64762582975152
1988	44.711208321676544
1989	44.77479081360157
1990	44.83837330552659
1991	45.11686462015819
1992	45.39535593478979
1993	45.6738472494214
1994	45.952338564053
1995	46.2308298786846
1996	46.50932119331621
1997	46.78781250794781
1998	47.066303822579414
1999	47.344795137211015
2000	47.623286451842624
2001	47.90506625295659
2002	48.18684605407056
2003	48.46862585518451
2004	48.750405656298476
2005	49.032185457412446
2006	49.31396525852641
2007	49.59574505964038
2008	49.87752486075434
2009	50.15930466186831
2010	50.441084462982275
2011	50.70358859584425
2012	50.96609272870622
2013	51.2285968615682
2014	51.49110099443017
2015	51.75360512729215
2016	52.14999109845113
2017	52.4319031511483
2018	52.66389277448562
2019	52.66389277448562
2020	52.66389277448562
2021	52.66389277448562