Year	% of land area
1961	61.763331879775585
1962	62.03779226273382
1963	62.39922655975424
1964	62.72910581466489
1965	63.29604298191948
1966	63.39618678000078
1967	63.72838393449878
1968	66.85101611496557
1969	66.5019615089231
1970	64.2297877588743
1971	65.02429828306627
1972	65.06059383257619
1973	64.81092901865327
1974	65.13114562045222
1975	65.02570844668915
1976	65.18126082032725
1977	63.979537378128946
1978	64.57701469611965
1979	64.20447001549016
1980	64.51687645626961
1981	64.5073740936959
1982	63.88347239758926
1983	62.974499824271376
1984	63.33493875532067
1985	63.365268213946344
1986	60.98967757051924
1987	61.312367389974355
1988	61.44670215950953
1989	60.80262421410255
1990	60.45546255678638
1991	60.24003228199888
1992	60.6594379287453
1993	59.89052757637686
1994	61.06803951941476
1995	60.318914908295696
1996	60.558686851593926
1997	60.168569308670584
1998	60.3830883980058
1999	59.05692305689703
2000	59.288103823073826
2001	59.318172942998835
2002	58.185699595173325
2003	57.20942946773753
2004	51.40465745935462
2005	53.39937258373143
2006	53.27857542663005
2007	51.853676633299926
2008	50.673366049230054
2009	50.018484047746114
2010	48.99209872043529
2011	51.562813219999214
2012	50.38543144631164
2013	48.39371021699231
2014	48.73839865665231
2015	45.31442406570949
2016	44.53992579322467
2017	48.34061793911093
2018	46.65809501275348
2019	47.12377242908885
2020	46.25247984274612
2021	47.25923749548233