Year	% of land area
1961	17.142857142857142
1962	17.142857142857142
1963	17.142857142857142
1964	17.142857142857142
1965	17.142857142857142
1966	17.142857142857142
1967	17.142857142857142
1968	17.142857142857142
1969	17.142857142857142
1970	17.142857142857142
1971	17.142857142857142
1972	17.142857142857142
1973	17.142857142857142
1974	17.142857142857142
1975	17.142857142857142
1976	17.142857142857142
1977	17.142857142857142
1978	17.142857142857142
1979	17.142857142857142
1980	23.076923076923077
1981	23.076923076923077
1982	19.230769230769234
1983	19.230769230769234
1984	15.384615384615385
1985	15.384615384615385
1986	11.538461538461538
1987	11.538461538461538
1988	11.538461538461538
1989	11.538461538461538
1990	7.6923076923076925
1991	7.6923076923076925
1992	7.6923076923076925
1993	7.6923076923076925
1994	3.8461538461538463
1995	3.8461538461538463
1996	3.8461538461538463
1997	3.8461538461538463
1998	3.8461538461538463
1999	3.8461538461538463
2000	1.9230769230769231
2001	1.153846153846154
2002	0.38461538461538464
2003	0.38461538461538464
2004	0.11538461538461539
2005	0.11538461538461539
2006	0.11538461538461539
2007	0.38461538461538464
2008	0.38461538461538464
2009	0.7692307692307693
2010	0.38461538461538464
2011	0.38461538461538464
2012	0.38461538461538464
2013	0.38461538461538464
2014	0.38461538461538464
2015	0.38461538461538464
2016	0.38461538461538464
2017	0.38461538461538464
2018	0.38461538461538464
2019	0.38461538461538464
2020	0.38461538461538464
2021	0.38461538461538464