Year	sq. km
1961	111700
1962	113830
1963	115850
1964	117930
1965	119950
1966	122030
1967	124050
1968	126150
1969	128200
1970	130250
1971	132350
1972	134380
1973	136450
1974	138480
1975	140550
1976	142580
1977	144650
1978	146730
1979	148750
1980	150800
1981	151850
1982	152920
1983	154050
1984	154150
1985	154270
1986	154350
1987	154400
1988	154400
1989	154450
1990	154550
1991	154600
1992	154650
1993	154650
1994	154750
1995	155150
1996	156660
1997	156660
1998	154500
1999	154500
2000	154500
2001	154500
2002	154500
2003	154500
2004	153850
2005	153850
2006	153850
2007	153850
2008	153850
2009	153850
2010	153510
2011	153510
2012	153550
2013	153550
2014	153500
2015	153500
2016	153500
2017	153500
2018	153500
2019	153500
2020	153500
2021	153500