Year	sq. km
1961	47100
1962	47100
1963	47200
1964	47200
1965	47300
1966	47300
1967	47400
1968	47350
1969	47950
1970	48550
1971	49150
1972	49750
1973	50350
1974	51680
1975	53850
1976	55550
1977	58350
1978	60050
1979	61900
1980	64780
1981	67590
1982	69600
1983	70950
1984	72550
1985	74200
1986	75800
1987	77210
1988	77260
1989	77530
1990	78460
1991	79140
1992	79530
1993	79750
1994	81290
1995	81080
1996	79870
1997	80120
1998	80270
1999	80750
2000	80660
2001	77850
2002	74900
2003	72500
2004	75270
2005	75000
2006	74440
2007	74120
2008	74450
2009	75344
2010	74977
2011	73461
2012	75069
2013	75130
2014	54750
2015	57890
2016	55160
2017	55900
2018	54480
2019	53300
2020	54200
2021	54700