Year	% of land area
1961	3.2877954764469135
1962	3.2877954764469135
1963	3.2911966441811686
1964	3.2957315344935094
1965	3.3002664248058498
1966	3.30253386996202
1967	3.312737373164787
1968	3.3093362054305313
1969	3.315004818320957
1970	3.3229408763675528
1971	3.3297432118360635
1972	3.292330366759254
1973	3.2877954764469135
1974	3.2945978119154242
1975	3.2957315344935094
1976	3.301400147383935
1977	3.3603537214443624
1978	3.350150218241596
1979	3.3433478827730854
1980	3.3524176633977665
1981	3.1789581089507397
1982	3.186894166997336
1983	3.0723881866107363
1984	3.071254464032651
1985	3.3070687602743605
1986	3.4975341533926647
1987	3.511138824329686
1988	3.511138824329686
1989	3.2254407346522305
1990	3.2107023411371234
1991	3.2243070120741457
1992	2.948812425599456
1993	2.9465449804432855
1994	2.9397426449747748
1995	2.9397426449747748
1996	2.9397426449747748
1997	2.9397426449747748
1998	2.9397426449747748
1999	2.9397426449747748
2000	2.9420100901309447
2001	2.9454112578652003
2002	2.9454112578652003
2003	2.9476787030213707
2004	3.0043648319256278
2005	3.0100334448160537
2006	3.0100334448160537
2007	3.014568335128394
2008	3.061050960829885
2009	2.9476787030213707
2010	2.9476787030213707
2011	2.9476787030213707
2012	2.9476787030213707
2013	2.9476787030213707
2014	2.9476787030213707
2015	2.9476787030213707
2016	2.9476787030213707
2017	2.9476787030213707
2018	2.9476787030213707
2019	2.9476787030213707
2020	2.9476787030213707
2021	2.9476787030213707