Year	sq. km
1961	3594945.7
1962	3594925.7
1963	3594935.7
1964	3594935.7
1965	3594925.7
1966	3594915.7
1967	3594905.7
1968	3594895.7
1969	3594895.7
1970	3594885.7
1971	3594875.7
1972	3594875.7
1973	3594875.7
1974	3594845.7
1975	3594725.7
1976	3594645.7
1977	3594625.7
1978	3594625.7
1979	3594585.7
1980	3594505.7
1981	3594485.7
1982	3594475.7
1983	3594435.7
1984	3594445.7
1985	3594445.7
1986	3594445.7
1987	3594445.7
1988	3594435.7
1989	3593445.7
1990	3593445.7
1991	3593555.7
1992	3836902.7
1993	3962252.7
1994	3962292.7
1995	3962262.7
1996	3962352.7
1997	3962262.7
1998	3962222.7
1999	3962192.7
2000	3996118.16
2001	3995588.16
2002	3994398.16
2003	3994880.16
2004	3994620.16
2005	3994330.16
2006	3993670.16
2007	3993620.16
2008	3993061.36
2009	3993990.96
2010	3995282.36
2011	3995188.16
2012	3995337.86
2013	3996728.36
2014	3997475.76
2015	3996852.3
2016	3997244.7
2017	3996523.1500000004
2018	3996556.579
2019	3996440.586
2020	3996449.1670000004
2021	3996581.774