Year	sq. km
1961	32000
1962	33000
1963	33500
1964	34000
1965	36030
1966	36530
1967	36050
1968	37070
1969	37570
1970	37070
1971	38570
1972	39070
1973	39570
1974	39600
1975	39100
1976	39120
1977	39150
1978	39680
1979	39700
1980	38300
1981	39300
1982	40300
1983	39400
1984	39900
1985	40050
1986	41050
1987	41100
1988	41150
1989	41650
1990	42180
1991	43200
1992	42700
1993	42700
1994	40700
1995	42800
1996	43800
1997	44300
1998	45800
1999	46800
2000	47300
2001	48300
2002	48300
2003	49800
2004	49800
2005	51800
2006	52850
2007	52850
2008	54350
2009	54850
2010	54850
2011	54850
2012	54850
2013	55450
2014	56510
2015	57060
2016	57620
2017	58170
2018	58730
2019	59280
2020	59840
2021	60500