Year	% of land area
1961	27.86885245901639
1962	27.86885245901639
1963	29.508196721311474
1964	29.508196721311474
1965	29.508196721311474
1966	29.508196721311474
1967	31.147540983606557
1968	31.147540983606557
1969	31.147540983606557
1970	31.147540983606557
1971	32.78688524590164
1972	32.78688524590164
1973	32.78688524590164
1974	32.622950819672134
1975	32.78688524590164
1976	32.78688524590164
1977	32.78688524590164
1978	32.78688524590164
1979	33.114754098360656
1980	33.60655737704918
1981	34.0983606557377
1982	34.42622950819672
1983	34.75409836065574
1984	35.24590163934426
1985	35.73770491803279
1986	34.75409836065574
1987	34.42622950819672
1988	34.42622950819672
1989	34.42622950819672
1990	34.26229508196722
1991	32.459016393442624
1992	32.295081967213115
1993	32.295081967213115
1994	31.967213114754102
1995	29.508196721311474
1996	28.524590163934427
1997	27.86885245901639
1998	25.40983606557377
1999	25.245901639344265
2000	23.278688524590162
2001	22.78688524590164
2002	21.475409836065573
2003	20.327868852459016
2004	18.19672131147541
2005	17.868852459016395
2006	16.557377049180328
2007	16.278688524590166
2008	16.295081967213115
2009	16.295081967213115
2010	16.295081967213115
2011	16.295081967213115
2012	16.295081967213115
2013	16.295081967213115
2014	16.295081967213115
2015	16.295081967213115
2016	16.295081967213115
2017	16.295081967213115
2018	16.295081967213115
2019	16.295081967213115
2020	16.295081967213115
2021	16.295081967213115