Year	% of land area
1990	55.16162669447341
1991	54.88313537984181
1992	54.60464406521021
1993	54.32615275057861
1994	54.047661435947006
1995	53.76917012131539
1996	53.49067880668379
1997	53.21218749205219
1998	52.933696177420586
1999	52.655204862788985
2000	52.37671354815738
2001	52.09493374704341
2002	51.81315394592946
2003	51.53137414481548
2004	51.249594343701524
2005	50.967814542587554
2006	50.6860347414736
2007	50.404254940359614
2008	50.12247513924566
2009	49.84069533813169
2010	49.558915537017725
2011	49.29641140415575
2012	49.03390727129378
2013	48.7714031384318
2014	48.50889900556983
2015	48.246394872707846
2016	47.850008901548875
2017	47.568096848851695
2018	47.33610722551438
2019	47.007947811490624
2020	46.72519646990004
2021	46.412173122409015