Year	% of land area
1961	55.319148936170215
1962	55.319148936170215
1963	55.319148936170215
1964	55.319148936170215
1965	55.319148936170215
1966	55.319148936170215
1967	55.319148936170215
1968	55.319148936170215
1969	55.319148936170215
1970	55.319148936170215
1971	53.191489361702125
1972	53.191489361702125
1973	51.06382978723404
1974	51.06382978723404
1975	51.06382978723404
1976	48.93617021276596
1977	48.93617021276596
1978	48.93617021276596
1979	48.93617021276596
1980	48.93617021276596
1981	48.93617021276596
1982	48.93617021276596
1983	48.93617021276596
1984	48.93617021276596
1985	48.93617021276596
1986	48.93617021276596
1987	48.93617021276596
1988	48.93617021276596
1989	48.93617021276596
1990	48.93617021276596
1991	48.93617021276596
1992	48.93617021276596
1993	48.93617021276596
1994	48.93617021276596
1995	48.93617021276596
1996	48.93617021276596
1997	48.93617021276596
1998	48.93617021276596
1999	48.93617021276596
2000	48.93617021276596
2001	48.40425531914894
2002	48.61702127659574
2003	48.638297872340424
2004	48.53191489361702
2005	46.38297872340426
2006	46.34042553191489
2007	44.19148936170213
2008	44.170212765957444
2009	44.19148936170213
2010	42.06382978723404
2011	42.06382978723404
2012	39.91489361702128
2013	40.02127659574468
2014	40
2015	40.02127659574468
2016	40.04255319148936
2017	40.04255319148936
2018	40.07234042553192
2019	40.00021276595744
2020	39.95170212765957
2021	39.9068085106383