Year	sq. km
1961	419290
1962	419290
1963	419290
1964	419290
1965	419290
1966	419290
1967	419290
1968	419290
1969	419290
1970	419290
1971	419290
1972	419290
1973	419290
1974	419290
1975	419290
1976	419290
1977	419290
1978	419290
1979	419290
1980	419290
1981	419290
1982	419290
1983	419290
1984	419290
1985	419290
1986	419290
1987	419290
1988	419290
1989	419290
1990	419290
1991	419290
1992	419290
1993	418900
1994	418610
1995	418530
1996	418400
1997	418540
1998	416110
1999	414530
2000	414060
2001	413850
2002	413960
2003	413550
2004	413540
2005	413040
2006	412840
2007	412660
2008	412920
2009	412760
2010	412670
2011	412810
2012	412970
2013	415260
2014	415110
2015	415080
2016	415150
2017	414890
2018	413290
2019	413110
2020	413110
2021	413110