Year	% of land area
1961	8.95638629283489
1962	8.95638629283489
1963	8.95638629283489
1964	8.95638629283489
1965	9.345794392523365
1966	9.345794392523365
1967	9.735202492211839
1968	9.735202492211839
1969	9.929906542056074
1970	10.12461059190031
1971	10.12461059190031
1972	10.514018691588785
1973	11.682242990654206
1974	11.682242990654206
1975	11.682242990654206
1976	11.682242990654206
1977	12.461059190031152
1978	12.461059190031152
1979	12.461059190031152
1980	12.461059190031152
1981	12.461059190031152
1982	12.461059190031152
1983	12.461059190031152
1984	12.461059190031152
1985	12.461059190031152
1986	13.239875389408098
1987	13.629283489096572
1988	14.018691588785046
1989	14.018691588785046
1990	14.018691588785046
1991	14.018691588785046
1992	14.40809968847352
1993	14.40809968847352
1994	14.40809968847352
1995	14.40809968847352
1996	14.40809968847352
1997	14.018691588785046
1998	14.018691588785046
1999	14.018691588785046
2000	14.018691588785046
2001	14.09657320872274
2002	14.213395638629283
2003	14.018691588785046
2004	14.797507788161992
2005	14.797507788161992
2006	15.57632398753894
2007	15.57632398753894
2008	15.57632398753894
2009	15.57632398753894
2010	15.57632398753894
2011	13.94080996884735
2012	13.629283489096572
2013	13.629283489096572
2014	13.629283489096572
2015	13.629283489096572
2016	13.629283489096572
2017	13.629283489096572
2018	13.629283489096572
2019	13.629283489096572
2020	13.629283489096572
2021	13.629283489096572