Year	% of land area
1961	5.540503332955421
1962	5.5297444001490055
1963	5.542817081946048
1964	5.57382131842045
1965	5.6143119257564225
1966	5.588050874712806
1967	5.609105990527512
1968	5.586894000217493
1969	5.599850994565004
1970	5.618939423737676
1971	5.691012704795708
1972	5.8120217770055
1973	5.887014486449466
1974	5.861216065821836
1975	5.789720891167685
1976	5.773293197315113
1977	5.699484262963417
1978	5.626947896445371
1979	5.723315987848134
1980	5.446127576082203
1981	5.537127744986662
1982	5.612526232250571
1983	5.589550598453946
1984	5.648507509307098
1985	5.680141231891938
1986	5.719359458765331
1987	5.773987325224377
1988	5.783705115954067
1989	5.756842365865566
1990	5.76776331163798
1991	5.994072147654889
1992	6.107397783880962
1993	6.222761842400572
1994	6.15002991691289
1995	6.143602651105861
1996	6.1228375601866745
1997	6.017100211246261
1998	6.032864353523972
1999	5.9544142833013645
2000	5.739421270855652
2001	5.803708598162412
2002	5.8315748489693355
2003	5.903710415039769
2004	5.851200558092398
2005	5.810467922991579
2006	5.85391828121692
2007	5.882925206506398
2008	5.623181517388185
2009	5.592047020757318
2010	5.595027588505407
2011	5.595540984668938
2012	5.621253182398904
2013	5.6064154305568925
2014	5.54562637251235
2015	5.554170186188338
2016	5.6181163739894355
2017	5.726507102804236
2018	5.728575366113215
2019	5.645265073146089
2020	5.780145313585899
2021	5.737323575354193