Year	% of land area
1961	42.924311857018836
1962	43.13941048329606
1963	43.36810970364724
1964	43.53654783025538
1965	43.85124465313568
1966	43.97867175761314
1967	44.25214831845393
1968	44.248172760186165
1969	43.921758502411386
1970	44.1165608575321
1971	43.87656268210411
1972	44.05734596333322
1973	44.44276587539805
1974	44.40154561335854
1975	44.53776079400687
1976	44.52583411920356
1977	44.576051697322754
1978	44.9420122978664
1979	44.94577861622534
1980	45.04893389127852
1981	44.863547332055155
1982	45.339484428679846
1983	44.794749250031856
1984	45.22549052634927
1985	45.120159156244256
1986	44.76918013317283
1987	44.976871666677475
1988	44.69159397497867
1989	44.92439429754292
1990	44.763405111689124
1991	44.704525001344365
1992	44.46668199697732
1993	44.46255997077337
1994	44.47473744206124
1995	44.38134392785
1996	44.20539029562389
1997	44.44496131827973
1998	44.45089139782243
1999	44.33633399549063
2000	44.30031240636714
2001	44.21880598328385
2002	44.213148725126395
2003	44.08764140526293
2004	43.87200277009994
2005	43.7816643110896
2006	43.622429676959314
2007	43.427709425403386
2008	43.29853171707839
2009	43.26939704004258
2010	43.06639750976064
2011	43.2020728798706
2012	43.12940386887551
2013	43.15560411800844
2014	43.14883397363249
2015	43.14935651648907
2016	43.25388241938368
2017	43.20481820619322
2018	43.14089340235181
2019	43.02555425770682
2020	42.93194888178914
2021	42.86696099888472