Year	% of land area
1990	17.42735899405126
1991	17.400438670710592
1992	17.373518347369927
1993	17.346598024029262
1994	17.319677700688597
1995	17.292757377347932
1996	17.265837054007264
1997	17.2389167306666
1998	17.21199640732593
1999	17.185076083985265
2000	17.158155760644597
2001	17.128633351990942
2002	17.09911094333728
2003	17.069588534683625
2004	17.040066126029966
2005	17.010543717376304
2006	16.98102130872265
2007	16.95149890006899
2008	16.92197649141533
2009	16.892454082761674
2010	16.862931674108015
2011	16.9553102586465
2012	17.047688843184986
2013	17.14006742772347
2014	17.232446012261953
2015	17.324824596800436
2016	17.425487713240475
2017	17.422913616969275
2018	17.42131455716444
2019	17.42131455716444
2020	17.42131455716444
2021	17.42131455716444