Year	% of land area
1992	0.42060787674786354
1993	0.4202481340742518
1994	0.42576494839593515
1995	0.3911926469157982
1996	0.38640754978954756
1997	0.38547358858129566
1998	0.3777920675990811
1999	0.37562141884044925
2000	0.37197899219502906
2001	0.3668437617971251
2002	0.36454710683140806
2003	0.36431429104572655
2004	0.36052045244379644
2005	0.366823677091708
2006	0.3786490108519483
2007	0.37885705798552494
2008	0.3795202712021325
2009	0.37928017688313903
2010	0.382418070455697
2011	0.3848892917400966
2012	0.39122238657663705
2013	0.3914922405579315
2014	0.38632915060371886
2015	0.3901017960412143
2016	0.39294654577614324
2017	0.3971610837913278
2018	0.40079943136212504
2019	0.4021604827951147
2020	0.40638114641692386
2021	0.40763386247152156