Year	% of land area
1990	5.344663278271919
1991	5.314723634053367
1992	5.284783989834816
1993	5.254844345616264
1994	5.224904701397713
1995	5.194965057179162
1996	5.16502541296061
1997	5.135085768742059
1998	5.105146124523507
1999	5.0752064803049555
2000	5.0452668360864035
2001	4.979907878017789
2002	4.9145489199491745
2003	4.849189961880559
2004	4.783831003811944
2005	4.718472045743329
2006	4.653113087674714
2007	4.587754129606099
2008	4.522395171537484
2009	4.45703621346887
2010	4.391677255400253
2011	4.290025412960611
2012	4.188373570520966
2013	4.086721728081322
2014	3.9850698856416775
2015	3.8834180432020333
2016	3.7873252858958066
2017	3.6936149936467597
2018	3.6014930114358323
2019	3.5117534942820843
2020	3.425190597204574
2021	3.3365099269377385