Year	% of land area
1961	43.722943722943725
1962	43.506493506493506
1963	43.83116883116883
1964	43.61471861471862
1965	43.506493506493506
1966	43.290043290043286
1967	43.3982683982684
1968	43.3982683982684
1969	43.18181818181818
1970	43.073593073593074
1971	42.857142857142854
1972	42.64069264069264
1973	42.66233766233766
1974	31.060606060606062
1975	19.51298701298701
1976	19.253246753246753
1977	19.058441558441558
1978	18.863636363636363
1979	18.66883116883117
1980	18.560606060606062
1981	19.036796536796537
1982	19.696969696969695
1983	19.805194805194805
1984	19.696969696969695
1985	17.61904761904762
1986	17.662337662337663
1987	17.575757575757574
1988	17.467532467532468
1989	17.467532467532468
1990	17.38095238095238
1991	17.22943722943723
1992	17.272727272727273
1993	17.175324675324674
1994	15.519480519480519
1995	15.487012987012989
1996	15.497835497835496
1997	15.38961038961039
1998	15.606060606060607
1999	15.606060606060607
2000	15.313852813852813
2001	15.151515151515152
2002	15.151515151515152
2003	16.666666666666664
2004	16.883116883116884
2005	18.073593073593074
2006	16.99134199134199
2007	15.930735930735931
2008	12.51082251082251
2009	13.80952380952381
2010	12.391774891774892
2011	12.586580086580087
2012	12.651515151515152
2013	11.778138528138529
2014	11.794372294372295
2015	13.70995670995671
2016	11.83874458874459
2017	13.140692640692642
2018	14.334080086580087
2019	13.563679653679653
2020	13.81485930735931
2021	13.326287878787879