Year	sq. km
1961	366700
1962	366700
1963	366700
1964	366700
1965	366700
1966	366700
1967	366700
1968	366700
1969	366700
1970	366700
1971	366700
1972	366600
1973	366600
1974	366600
1975	366500
1976	366500
1977	366400
1978	366400
1979	366400
1980	366300
1981	366400
1982	366200
1983	366200
1984	364700
1985	364600
1986	364700
1987	364600
1988	364600
1989	364600
1990	364600
1991	364600
1992	364600
1993	364600
1994	364600
1995	364600
1996	364500
1997	364500
1998	364500
1999	364500
2000	364500
2001	364500
2002	364500
2003	364500
2004	364500
2005	364500
2006	364500
2007	364500
2008	364500
2009	364500
2010	364500
2011	364500
2012	364500
2013	364500
2014	364500
2015	364500
2016	364500
2017	364500
2018	364500
2019	364500
2020	364500
2021	364500