Year	% of land area
1992	32.07344955701629
1993	32.459274078308084
1994	31.937696484709914
1995	32.73792512146328
1996	32.7593598170906
1997	32.59502715061446
1998	32.487853672477854
1999	32.637896541869104
2000	32.67362103458131
2001	32.67362103458131
2002	32.659331237496424
2003	32.837953701057444
2004	33.223778222349246
2005	33.38096599028294
2006	33.8310945984567
2007	33.78822520720205
2008	33.773935410117176
2009	34.00543012289226
2010	33.978993998285226
2011	33.958273792512145
2012	33.93112317805087
2013	34.156901971992
2014	34.673526148170566
2015	34.90020894877153
2016	35.127891058433605
2017	35.356293681100944
2018	35.38871676633763
2019	35.436270624684774
2020	35.42041933856906
2021	35.42762446862166