Year	sq. km
1961	10340
1962	10310
1963	10280
1964	10190
1965	10110
1966	10050
1967	10000
1968	9940
1969	9860
1970	9540
1971	9310
1972	9100
1973	9040
1974	9010
1975	8980
1976	8960
1977	8990
1978	9000
1979	9540
1980	9360
1981	9360
1982	9420
1983	9450
1984	9540
1985	9570
1986	9690
1987	9700
1988	9760
1989	9910
1990	9760
1991	10100
1992	10030
1993	10130
1994	10300
1995	11270
1996	11320
1997	10380
1998	10470
1999	10380
2000	10420
2001	10470
2002	10460
2003	10400
2004	10400
2005	10360
2006	10350
2007	10320
2008	10248
2009	10142.6
2010	10059
2011	9990
2012	9928
2013	9871.428
2014	9867.6
2015	9860.3
2016	9836.61
2017	9851.12
2018	9862.8
2019	9842.54
2020	9859.62
2021	9850