Year	% of land area
1961	9.500181787654931
1962	9.50764949154126
1963	9.575964714292041
1964	9.59736860685809
1965	9.629799752745695
1966	9.647481167528328
1967	9.66414824125709
1968	9.772111324581063
1969	9.83696738011242
1970	9.820596739343788
1971	9.78614412553579
1972	9.833335798520698
1973	9.845401420617845
1974	9.855452851752679
1975	9.857397971028462
1976	9.90690162997443
1977	9.953272359323798
1978	10.052850215636308
1979	10.103495575713143
1980	10.123792914511068
1981	10.149618188509704
1982	10.238335097475943
1983	10.280501061826294
1984	10.421594047645005
1985	10.532427432182622
1986	10.533858508681904
1987	10.534619219492642
1988	10.517071683814356
1989	10.526368732795756
1990	10.531086490572783
1991	10.55057663412506
1992	10.516681849184602
1993	10.528650683856208
1994	10.502337788452875
1995	10.499125686525623
1996	10.492754979087746
1997	10.524657937756867
1998	10.520465518341146
1999	10.532335225819894
2000	10.508081614934637
2001	10.512957331770213
2002	10.495125925932625
2003	10.521541372953427
2004	10.529330353400729
2005	10.548460919422304
2006	10.54379953831975
2007	10.532760897634587
2008	10.528178194409483
2009	10.571116389473271
2010	10.567794181977083
2011	10.629363298333757
2012	10.65580127919058
2013	10.675257358281112
2014	10.692646762258848
2015	10.714988311402262
2016	10.730751287279839
2017	10.750842448316718
2018	10.75138027946863
2019	10.738604892068617
2020	10.76301449819158
2021	10.795379054534035