Year	% of land area
1990	62.75604930756353
1991	62.47385481661848
1992	62.19166032567342
1993	61.90946583472835
1994	61.627271343783285
1995	61.34507685283823
1996	61.062882361893166
1997	60.780687870948114
1998	60.49849338000304
1999	60.21629888905798
2000	59.93410439811292
2001	59.70774615735809
2002	59.48138791660325
2003	59.25502967584843
2004	59.02867143509359
2005	58.802313194338765
2006	58.57595495358393
2007	58.3495967128291
2008	58.12323847207427
2009	57.896880231319436
2010	57.6705219905646
2011	57.98497641150511
2012	58.299430832445594
2013	58.61388525338609
2014	58.928339674326594
2015	59.24279409526708
2016	58.78752092527774
2017	58.6348805356871
2018	58.48224014609649
2019	58.32959975650586
2020	58.17695936691523
2021	58.024318977324604