Year	sq. km
1961	50
1962	50
1963	50
1964	50
1965	50
1966	50
1967	50
1968	50
1969	50
1970	50
1971	50
1972	50
1973	50
1974	50
1975	50
1976	50
1977	50
1978	50
1979	50
1980	50
1981	50
1982	60
1983	60
1984	60
1985	60
1986	60
1987	60
1988	50
1989	50
1990	40
1991	40
1992	40
1993	40
1994	40
1995	40
1996	40
1997	40
1998	40
1999	40
2000	40
2001	40
2002	40
2003	40
2004	40
2005	40
2006	40
2007	30
2008	30
2009	29
2010	24
2011	15
2012	15
2013	15.5
2014	15.5
2015	15.5
2016	15.5
2017	15.5
2018	15.5
2019	15.5
2020	15.5
2021	15.5