Year	% of land area
1961	1.7317193675889329
1962	1.7341897233201582
1963	1.7366600790513833
1964	1.7440711462450593
1965	1.7020750988142292
1966	1.7119565217391304
1967	1.7218379446640317
1968	1.7218379446640317
1969	1.7193675889328064
1970	1.70701581027668
1971	1.7243083003952568
1972	1.7193675889328064
1973	1.7514822134387351
1974	1.7546936758893281
1975	1.7484071714328049
1976	1.7530169901713835
1977	1.7625655652689287
1978	1.7647058823529411
1979	1.746349335704055
1980	1.750854143509942
1981	1.7450907743608743
1982	1.7094397925157465
1983	1.6762586143015932
1984	1.682845498332716
1985	1.6770821291836482
1986	1.689102877608991
1987	1.7088057305174755
1988	1.7156149191058416
1989	1.7372441645053724
1990	1.7388662467580585
1991	1.7725989872792391
1992	1.8063314807953563
1993	1.914412745461282
1994	1.8812071137458317
1995	1.876900827466963
1996	1.8735828084475732
1997	1.8556914906755588
1998	1.8479271335062368
1999	1.849796220822527
2000	1.8517147091515376
2001	1.848915153760652
2002	1.8214153390144499
2003	1.8507266888971223
2004	1.8331068296900086
2005	1.8060269235519328
2006	1.806298629121897
2007	1.7924169445473632
2008	1.7825614425095715
2009	1.82208225268618
2010	1.818377176732123
2011	1.8270223539582562
2012	1.817142151414104
2013	1.8356675311843893
2014	1.8467827590465604
2015	1.8690132147709029
2016	1.8665431641348649
2017	1.8640731134988267
2018	1.8640731134988267
2019	1.8690132147709029
2020	1.8788934173150549
2021	1.8788934173150549