Year	% of land area
1992	59.43396226415094
1993	59.65739821251241
1994	59.88083416087389
1995	60.104270109235344
1996	60.32770605759682
1997	60.55114200595829
1998	60.77457795431977
1999	60.99801390268124
2000	61.2214498510427
2001	61.29096325719961
2002	61.3604766633565
2003	61.42999006951341
2004	61.4995034756703
2005	61.56901688182721
2006	61.6385302879841
2007	61.70804369414101
2008	61.75854503578838
2009	61.82926466062405
2010	61.897529062552735
2011	61.908071081107906
2012	61.91892066297026
2013	61.94637537239325
2014	61.95630585898709
2015	61.958237764737426
2016	61.859298977261446
2017	61.769978299839615
2018	61.67438072346596
2019	61.57307165133788
2020	61.47225919230846
2021	61.371114002502935