Year	% of land area
1961	83.53460996298708
1962	82.54540058857958
1963	81.60565168289244
1964	80.57934695694466
1965	79.63959805125754
1966	79.48627059822438
1967	79.25875244211065
1968	79.0765730489906
1969	78.88615024441715
1970	78.69572743984371
1971	78.50530463527025
1972	78.31900353642351
1973	78.12445902612338
1974	77.94640133873003
1975	77.73949171124978
1976	77.54494720094965
1977	77.53587944835091
1978	77.54329851865897
1979	77.53423076606023
1980	77.53340642491489
1981	77.52433867231615
1982	77.51527091971741
1983	77.51527091971741
1984	77.51527091971741
1985	77.51527091971741
1986	77.81780412005705
1987	78.02388940639194
1988	78.22997469272683
1989	78.55971115086268
1990	78.80701349446456
1991	79.14087165832709
1992	79.52666331434601
1993	79.90833326463824
1994	80.17954150145496
1995	80.38974849351655
1996	80.6947547172922
1997	80.74009348028588
1998	80.77554014953549
1999	80.83324402970925
2000	80.888474886447
2001	80.79614867816898
2002	80.80851379534907
2003	80.7260796808151
2004	80.46229051430645
2005	80.35924787113899
2006	79.86876488966193
2007	79.87041357195261
2008	80.05011994163664
2009	79.9511990041959
2010	79.87123791309796
2011	79.44505354095739
2012	79.41785028316119
2013	79.41785028316119
2014	79.41785028316119
2015	79.41785028316119
2016	79.41785028316119
2017	79.41785028316119
2018	79.41785028316119
2019	79.41785028316119
2020	79.41785028316119
2021	79.41785028316119