Year	% of land area
1990	10.766355140186915
1991	10.444937694704052
1992	10.123520249221183
1993	9.802102803738318
1994	9.480685358255451
1995	9.159267912772586
1996	8.83785046728972
1997	8.516433021806852
1998	8.195015576323987
1999	7.873598130841122
2000	7.552180685358256
2001	7.552180685358256
2002	7.552180685358256
2003	7.552180685358256
2004	7.552180685358256
2005	7.552180685358256
2006	7.552180685358256
2007	7.552180685358256
2008	7.552180685358256
2009	7.552180685358256
2010	7.552180685358256
2011	8.219626168224298
2012	8.887071651090341
2013	9.554517133956386
2014	10.221962616822431
2015	10.889408099688474
2016	10.889408099688474
2017	10.889408099688474
2018	10.889408099688474
2019	10.889408099688474
2020	10.889408099688474
2021	10.889408099688474