Year	% of land area
1961	35.8793167047376
1962	35.95247026261608
1963	36.03538341426645
1964	36.1170428251459
1965	36.21394093364546
1966	36.294320909967105
1967	36.389050836517825
1968	36.7015793277098
1969	36.74275359513358
1970	36.650371582575424
1971	36.797793691702864
1972	36.93124131068155
1973	37.0246451755561
1974	37.14678579787669
1975	37.242388525921115
1976	37.24294553918096
1977	37.28966253229293
1978	37.45449902392719
1979	37.532416659843385
1980	37.65427139687117
1981	37.70388827036709
1982	37.82520671853376
1983	37.89313471781113
1984	38.138917248576774
1985	38.40178882744221
1986	38.38763150719191
1987	38.5524445258239
1988	38.71116564272507
1989	38.816107470661585
1990	38.92994784329453
1991	38.97328951563356
1992	37.11346503548914
1993	37.001242512307584
1994	37.176222754802126
1995	37.16720184411482
1996	37.2287421821785
1997	37.36490695768079
1998	37.475908137717475
1999	37.496551410495215
2000	37.52018410756656
2001	37.535860187606
2002	37.47500405077773
2003	37.331860075478744
2004	36.97053503887833
2005	37.02644678698428
2006	37.037442160419104
2007	36.97291800549983
2008	36.85593542784667
2009	36.810781713721575
2010	36.805434007783376
2011	36.94991875340736
2012	36.86775299998143
2013	36.7902324763962
2014	36.78905099263534
2015	36.620495521649204
2016	36.58701415369825
2017	36.83400084059795
2018	36.73845806571344
2019	36.76264775998086
2020	36.730920286540425
2021	36.84166549584336