Year	% of land area
1961	85.01317523056655
1962	84.84848484848484
1963	84.84848484848484
1964	84.91436100131752
1965	84.91436100131752
1966	85.0790513833992
1967	85.0790513833992
1968	83.43214756258234
1969	81.62055335968378
1970	79.9407114624506
1971	77.86561264822134
1972	77.70092226613966
1973	77.70092226613966
1974	77.70092226613966
1975	78.26086956521739
1976	77.70092226613966
1977	75.49407114624506
1978	75.5270092226614
1979	76.0540184453228
1980	75.6258234519104
1981	75.82345191040844
1982	75.49407114624506
1983	75.32938076416337
1984	75.7905138339921
1985	76.02108036890645
1986	75.46113306982872
1987	76.74571805006588
1988	77.17391304347827
1989	75.92226613965745
1990	76.44927536231883
1991	76.51515151515152
1992	76.9433465085639
1993	76.87747035573122
1994	76.71277997364953
1995	76.54808959156784
1996	76.61396574440053
1997	76.71277997364953
1998	76.71277997364953
1999	76.71277997364953
2000	76.87747035573122
2001	76.87747035573122
2002	75.8893280632411
2003	75.8893280632411
2004	76.21870882740448
2005	76.64690382081687
2006	75.98814229249012
2007	76.71277997364953
2008	77.79973649538867
2009	77.04216073781292
2010	76.61396574440053
2011	76.1528326745718
2012	75.2733860342556
2013	74.1798418972332
2014	74.97694334650856
2015	73.22134387351778
2016	77.60210803689066
2017	79.64426877470355
2018	80.14822134387352
2019	80.13833992094862
2020	80.13833992094862
2021	80.13833992094862