Year	% of land area
1961	4.347756920139994
1962	4.33184855233853
1963	4.459115494750239
1964	4.459115494750239
1965	4.619790009545021
1966	4.635698377346484
1967	4.556156538339167
1968	4.715240216353802
1969	4.715240216353802
1970	4.778873687559656
1971	4.778873687559656
1972	4.79478205536112
1973	4.79478205536112
1974	4.79478205536112
1975	4.8743238943684375
1976	4.922048997772828
1977	4.953865733375756
1978	4.953865733375756
1979	5.01749920458161
1980	5.033407572383074
1981	5.081132675787464
1982	5.1129494113903915
1983	5.097041043588928
1984	5.144766146993319
1985	5.176582882596246
1986	5.2402163538021
1987	5.272033089405027
1988	5.335666560610881
1989	4.96500159083678
1990	4.985682468978683
1991	5.348909657320872
1992	5.395638629283489
1993	5.395638629283489
1994	5.395638629283489
1995	5.520249221183801
1996	5.5514018691588785
1997	5.5514018691588785
1998	5.535825545171339
1999	5.520249221183801
2000	5.520249221183801
2001	5.546728971962617
2002	5.593457943925234
2003	5.6246105919003115
2004	5.6246105919003115
2005	5.733644859813084
2006	5.82398753894081
2007	5.836448598130841
2008	5.844236760124611
2009	5.906542056074766
2010	5.975077881619938
2011	6.012461059190031
2012	5.987538940809969
2013	5.970404984423676
2014	5.968847352024922
2015	5.98411214953271
2016	5.987383177570093
2017	6.026500389711614
2018	6.014029618082619
2019	5.930007794232268
2020	5.895713172252533
2021	5.692828999211978