Year	% of land area
1961	8.797653958944283
1962	8.797653958944283
1963	8.797653958944283
1964	8.797653958944283
1965	8.797653958944283
1966	8.797653958944283
1967	8.797653958944283
1968	8.797653958944283
1969	8.797653958944283
1970	8.797653958944283
1971	8.797653958944283
1972	9.286412512218964
1973	10.263929618768328
1974	10.068426197458455
1975	9.872922776148583
1976	9.67741935483871
1977	9.481915933528837
1978	9.286412512218964
1979	9.090909090909092
1980	8.895405669599219
1981	8.60215053763441
1982	8.797653958944283
1983	8.797653958944283
1984	8.797653958944283
1985	9.286412512218964
1986	9.775171065493646
1987	11.339198435972628
1988	11.534701857282501
1989	11.730205278592376
1990	11.925708699902248
1991	12.218963831867057
1992	12.316715542521994
1993	12.316715542521994
1994	12.41446725317693
1995	12.609970674486803
1996	13.196480938416421
1997	13.391984359726294
1998	13.587487781036167
1999	13.294232649071358
2000	13.78299120234604
2001	13.978494623655912
2002	13.78299120234604
2003	13.78299120234604
2004	13.880742913000976
2005	13.812316715542522
2006	13.978494623655912
2007	13.96871945259042
2008	13.685239491691103
2009	13.685239491691103
2010	12.316715542521994
2011	12.316715542521994
2012	12.316715542521994
2013	12.512218963831867
2014	12.70772238514174
2015	12.903225806451612
2016	13.098729227761485
2017	13.308895405669599
2018	13.134897360703812
2019	13.294232649071358
2020	13.685239491691103
2021	13.685239491691103