Year	% of land area
1990	37.14754098360656
1991	37.01857923497268
1992	36.8896174863388
1993	36.760655737704916
1994	36.63169398907104
1995	36.502732240437155
1996	36.373770491803285
1997	36.2448087431694
1998	36.11584699453552
1999	35.98688524590164
2000	35.857923497267755
2001	35.826229508196725
2002	35.79453551912568
2003	35.762841530054644
2004	35.731147540983606
2005	35.711162129659996
2006	35.67945774570897
2007	35.64775336175796
2008	35.61604897780693
2009	35.53772245878371
2010	35.50605961349492
2011	35.63707828365542
2012	35.76809695381592
2013	35.89315890364303
2014	36.023998532840785
2015	36.154994891142024
2016	36.154994891142024
2017	36.154994891142024
2018	36.154994891142024
2019	36.154994891142024
2020	36.154994891142024
2021	36.154994891142024