Year	sq. km
1961	38750
1962	38810
1963	38870
1964	38930
1965	38990
1966	39050
1967	39110
1968	39130
1969	39230
1970	39290
1971	39350
1972	39410
1973	39460
1974	39510
1975	39560
1976	39610
1977	39660
1978	39710
1979	39760
1980	39790
1981	39820
1982	39850
1983	39880
1984	39910
1985	39940
1986	39970
1987	40010
1988	40050
1989	40050
1990	39630
1991	39200
1992	38780
1993	39590
1994	39520
1995	39240
1996	37300
1997	35820
1998	37225
1999	38630
2000	39563.8
2001	38538.2
2002	38777.2
2003	38136.8
2004	38696.1
2005	38238.9
2006	37576.6
2007	36609.2
2008	37258.6
2009	36955.8
2010	36541.7
2011	36493.6
2012	36644.1
2013	37011
2014	36638.8
2015	36387.8
2016	36190.3
2017	36733.928
2018	37367.665
2019	39505.205
2020	39542.556000000004
2021	39622.955