Year	sq. km
1961	70830
1962	70120
1963	69840
1964	69790
1965	69530
1966	69270
1967	69140
1968	69030
1969	68880
1970	68750
1971	68550
1972	68460
1973	68350
1974	67820
1975	67700
1976	67570
1977	67290
1978	66980
1979	66510
1980	66270
1981	66010
1982	65820
1983	65710
1984	65540
1985	65390
1986	65230
1987	65110
1988	64970
1989	64840
1990	64740
1991	64600
1992	61360
1993	61300
1994	61220
1995	61790
1996	61840
1997	61950
1998	61930
1999	61860
2000	58540
2001	58650
2002	58490
2003	58650
2004	58640
2005	58630
2006	58090
2007	58070
2008	57900
2009	57830
2010	53430
2011	53370
2012	53380
2013	52570
2014	52640
2015	52640
2016	52820
2017	53030
2018	52960
2019	52780
2020	49166.725999999995
2021	50436.886