Year	sq. km
1961	4040
1962	4020
1963	4050
1964	4030
1965	4020
1966	4000
1967	4010
1968	4010
1969	3990
1970	3980
1971	3960
1972	3940
1973	3942
1974	2870
1975	1803
1976	1779
1977	1761
1978	1743
1979	1725
1980	1715
1981	1759
1982	1820
1983	1830
1984	1820
1985	1628
1986	1632
1987	1624
1988	1614
1989	1614
1990	1606
1991	1592
1992	1596
1993	1587
1994	1434
1995	1431
1996	1432
1997	1422
1998	1442
1999	1442
2000	1415
2001	1400
2002	1400
2003	1540
2004	1560
2005	1670
2006	1570
2007	1472
2008	1156
2009	1276
2010	1145
2011	1163
2012	1169
2013	1088.3
2014	1089.8
2015	1266.8
2016	1093.9
2017	1214.2
2018	1324.469
2019	1253.2839999999999
2020	1276.493
2021	1231.349