Year	sq. km
1961	46723
1962	46723
1963	46723
1964	46723
1965	46723
1966	46723
1967	46723
1968	46723
1969	46723
1970	46723
1971	46723
1972	46723
1973	46723
1974	46723
1975	46723
1976	46723
1977	46723
1978	46723
1979	46723
1980	46723
1981	46723
1982	46723
1983	46723
1984	46723
1985	46723
1986	46723
1987	46723
1988	46723
1989	46723
1990	46723
1991	46723
1992	46723
1993	46723
1994	39800
1995	39800
1996	39800
1997	39800
1998	39800
1999	39800
2000	39800
2001	39800
2002	39800
2003	39800
2004	38117
2005	38117
2006	38117
2007	38117
2008	38117
2009	38117
2010	38117
2011	38117
2012	38117
2013	38117
2014	38117
2015	38117
2016	38144
2017	38144
2018	38140
2019	38140
2020	38140
2021	38140