Year	% of land area
1992	35.29851683174918
1993	35.216826962113394
1994	35.13873053358603
1995	35.056684873643064
1996	34.973506594382364
1997	34.88982889478469
1998	34.81794620306659
1999	34.731534747457
2000	34.62388464999475
2001	34.57024642084049
2002	34.517464399796204
2003	34.46045018647925
2004	34.40719000094947
2005	34.35190903118887
2006	34.29680547192085
2007	34.24353627201412
2008	34.19051086287628
2009	34.13825149621908
2010	34.08473328668383
2011	34.03685099293104
2012	33.989179132013064
2013	33.94276766904124
2014	33.895428969742376
2015	33.84591353300944
2016	33.81807002963002
2017	33.76177579141595
2018	33.72374579585469
2019	33.68333404339442
2020	33.64500541267417
2021	33.59818642711594