Year	% of land area
1961	49.2151431209603
1962	49.39981532779317
1963	49.39981532779317
1964	49.2151431209603
1965	46.81440443213297
1966	47.73776546629732
1967	47.73776546629732
1968	47.73776546629732
1969	47.73776546629732
1970	46.81440443213297
1971	46.81440443213297
1972	46.81440443213297
1973	46.81440443213297
1974	46.81440443213297
1975	46.81440443213297
1976	46.81440443213297
1977	46.81440443213297
1978	46.81440443213297
1979	45.89104339796861
1980	45.89104339796861
1981	45.89104339796861
1982	44.96768236380424
1983	44.04432132963989
1984	44.04432132963989
1985	44.04432132963989
1986	44.04432132963989
1987	44.04432132963989
1988	44.04432132963989
1989	44.04432132963989
1990	43.95198522622346
1991	43.95198522622346
1992	43.95198522622346
1993	46.445060018467224
1994	46.16805170821791
1995	45.89104339796861
1996	45.614035087719294
1997	45.15235457063712
1998	44.69067405355494
1999	44.50600184672207
2000	44.22899353647276
2001	44.22899353647276
2002	43.76731301939058
2003	43.76731301939058
2004	43.58264081255771
2005	43.12096029547553
2006	43.12096029547553
2007	42.84395198522623
2008	41.45891043397968
2009	41.18190212373038
2010	38.901200369344416
2011	38.827331486611264
2012	38.76269621421976
2013	38.67036011080332
2014	38.58725761772853
2015	38.504155124653735
2016	38.504155124653735
2017	38.504155124653735
2018	38.504155124653735
2019	38.504155124653735
2020	38.504155124653735
2021	38.504155124653735