Year	sq. km
1961	31600
1962	31410
1963	30880
1964	30680
1965	30330
1966	30270
1967	30230
1968	30170
1969	29910
1970	29750
1971	29510
1972	29560
1973	29860
1974	29320
1975	29370
1976	29330
1977	29270
1978	29210
1979	29200
1980	29050
1981	28970
1982	28870
1983	28460
1984	28550
1985	28340
1986	28190
1987	27980
1988	27870
1989	27740
1990	27880
1991	27700
1992	27560
1993	27390
1994	26910
1995	27260
1996	27160
1997	26880
1998	26720
1999	26440
2000	26470
2001	26760
2002	26650
2003	26580
2004	26460
2005	27070
2006	27100
2007	26630
2008	26680
2009	26340
2010	26260
2011	26900
2012	26240
2013	26280
2014	26526.31
2015	26338.99
2016	26251
2017	26313
2018	26325
2019	26259.65
2020	26199.87
2021	26180