Year	sq. km
1961	230340
1962	230340
1963	230340
1964	230340
1965	230340
1966	230340
1967	230340
1968	230340
1969	230340
1970	230340
1971	230340
1972	230340
1973	230340
1974	230340
1975	230340
1976	230340
1977	230340
1978	230340
1979	230340
1980	230340
1981	230340
1982	230340
1983	230340
1984	230340
1985	230340
1986	230340
1987	230340
1988	230340
1989	229350
1990	229350
1991	229460
1992	229460
1993	229460
1994	229510
1995	229490
1996	229520
1997	229530
1998	229590
1999	229600
2000	229710
2001	229710
2002	229870
2003	229950
2004	230000
2005	229980
2006	229980
2007	229890
2008	229900
2009	230060
2010	230050
2011	230170
2012	230020
2013	230030
2014	230080
2015	230080
2016	230080
2017	230080
2018	230080
2019	230080
2020	230080
2021	230080