Year	% of land area
1961	0.7574520878905613
1962	0.7803062457148454
1963	0.777041366025662
1964	0.7868360050932123
1965	0.7998955238499462
1966	0.8031604035391295
1967	0.7411276894446439
1968	0.7476574488230109
1969	0.7476574488230109
1970	0.777041366025662
1971	0.9696692676874856
1972	0.9892585458225864
1973	1.0023180645793204
1974	1.0251722224036044
1975	1.0382317411603381
1976	1.0545561396062555
1977	1.0676156583629894
1978	1.0806751771197232
1979	1.0969995755656403
1980	1.1100590943223743
1981	1.1296483724574748
1982	1.100264455254824
1983	1.0610858989846226
1984	1.0708805380521726
1985	1.0904698161872735
1986	1.093734695876457
1987	1.100264455254824
1988	1.0317019817819713
1989	1.1263834927682914
1990	1.1263834927682914
1991	1.159032289660126
1992	1.1818864474844102
1993	1.1851513271735936
1994	1.1492376505925757
1995	1.1916810865519605
1996	1.1263834927682914
1997	1.0284371020927878
1998	1.051291259917072
1999	1.0741454177413563
2000	1.100264455254824
2001	1.1100590943223743
2002	1.0676156583629894
2003	1.0253396029258097
2004	1.1490875852838442
2005	1.233963372833219
2006	1.2176808566205277
2007	1.2242099764951684
2008	1.2210251387528566
2009	1.2178398850724828
2010	1.2733446519524618
2011	1.273552558534435
2012	1.2997191561622363
2013	1.3454818588550341
2014	1.2279956889513048
2015	1.2769848786701068
2016	1.2835167706326138
2017	1.2541232568013325
2018	1.1529542411078813
2019	1.1107118356146484
2020	1.2413027145330415
2021	1.2414243711205488