Year	% of land area
1990	25.590000000000003
1991	25.824041117145075
1992	26.058081458494957
1993	26.292122575640033
1994	26.526162916989914
1995	26.760204034134986
1996	26.994245151280065
1997	27.22828549262995
1998	27.46232660977502
1999	27.6963669511249
2000	27.93040806826998
2001	28.164366951124904
2002	28.398326609775022
2003	28.63228549262995
2004	28.866245151280058
2005	29.10020403413499
2006	29.33416291698992
2007	29.568122575640025
2008	29.80208145849496
2009	30.036041117145075
2010	30.269999999999996
2011	30.269999999999996
2012	30.269999999999996
2013	30.269999999999996
2014	30.269999999999996
2015	30.269999999999996
2016	30.2699767261443
2017	30.2699767261443
2018	30.2699767261443
2019	30.2699767261443
2020	30.2699767261443
2021	30.2699767261443