Year	% of land area
1992	33.56307434080024
1993	33.476053702149905
1994	33.3919170164553
1995	33.30460850576705
1996	33.21639069483769
1997	33.12777221990056
1998	33.04861135029317
1999	32.95779923737789
2000	32.849966774735975
2001	32.78735477906943
2002	32.725428321699276
2003	32.6601791245936
2004	32.54602021871014
2005	32.482180954423065
2006	32.420448553364984
2007	32.35824947456398
2008	32.29627720233459
2009	32.234890695741974
2010	32.1722790711424
2011	32.11023101751434
2012	32.00602569220926
2013	31.945336441773183
2014	31.88391425335954
2015	31.820733319523463
2016	31.774579227823594
2017	31.705196578454835
2018	31.651776456961308
2019	31.595556337018557
2020	31.541482070070003
2021	31.480368573762746