Year	% of land area
1961	0.7857562049552343
1962	0.7887956880398135
1963	0.7916358607581906
1964	0.7944760334765677
1965	0.7948746542089715
1966	0.7973162061949449
1967	0.8012027583358821
1968	0.8039931034627087
1969	0.8154534495193182
1970	0.822030691603981
1971	0.836362701437325
1972	0.8442851148017488
1973	0.8529549256533824
1974	0.8597113989377588
1975	0.8620671614669257
1976	0.8853417089643607
1977	0.9118992197772039
1978	0.9379584658468418
1979	0.9666834282926281
1980	0.9976052292521381
1981	1.0127276320230605
1982	1.0127027186741793
1983	1.0162155008664364
1984	1.021123430596044
1985	1.0077449622468093
1986	1.0077648929259144
1987	1.0148078966546454
1988	1.0097629435061912
1989	1.0068605383615248
1990	1.0053532807542087
1991	1.0141103228859703
1992	1.0163898943086052
1993	1.0158791706565395
1994	1.029912860081351
1995	0.992585189452565
1996	0.9958513294908977
1997	1.0205379668973344
1998	1.0490950538498869
1999	1.0660976288605575
2000	1.0869123732940167
2001	1.105549091610922
2002	1.114342303760186
2003	1.1066222184120804
2004	1.1600510616418327
2005	1.190123992259129
2006	1.2078889579060237
2007	1.2047581347059664
2008	1.1944791054665236
2009	1.181161172571704
2010	1.174130626550078
2011	1.175543329784694
2012	1.1623728170956857
2013	1.1568227052912026
2014	1.1523435928725974
2015	1.1587002450697346
2016	1.1388990503906125
2017	1.1332713022368026
2018	1.1544465373167132
2019	1.1650797744900405
2020	1.1769805549789703
2021	1.1878999785541848