Year	sq. km
1961	25810
1962	25760
1963	25760
1964	25780
1965	25780
1966	25830
1967	25830
1968	25330
1969	24780
1970	24270
1971	23640
1972	23590
1973	23590
1974	23590
1975	23760
1976	23590
1977	22920
1978	22930
1979	23090
1980	22960
1981	23020
1982	22920
1983	22870
1984	23010
1985	23080
1986	22910
1987	23300
1988	23430
1989	23050
1990	23210
1991	23230
1992	23360
1993	23340
1994	23290
1995	23240
1996	23260
1997	23290
1998	23290
1999	23290
2000	23340
2001	23340
2002	23040
2003	23040
2004	23140
2005	23270
2006	23070
2007	23290
2008	23620
2009	23390
2010	23260
2011	23120
2012	22853
2013	22521
2014	22763
2015	22230
2016	23560
2017	24180
2018	24333
2019	24330
2020	24330
2021	24330