Year	% of land area
1992	57.58522482092
1993	57.536894795891946
1994	57.46267368602744
1995	57.454043324415295
1996	57.28661430913955
1997	57.10019849831708
1998	56.71528437041512
1999	56.39078277379822
2000	56.20781910762061
2001	56.16121515491499
2002	56.174267269651665
2003	56.0637967342148
2004	56.0672489384472
2005	56.01159860540578
2006	56.00317591825462
2007	55.98536240139471
2008	56.055375267555064
2009	56.06227991438239
2010	56.060553752675546
2011	56.098529310225786
2012	56.13132638265552
2013	56.57840226472416
2014	56.56924856289596
2015	56.57787981839838
2016	56.579606069498865
2017	56.57345071638184
2018	56.76389368312047
2019	56.82430100103555
2020	56.82430100103555
2021	56.82430100103555