Year	% of land area
1961	2.2971845989955866
1962	2.36782833663065
1963	2.43758940800487
1964	2.4684827271343783
1965	2.353796986760006
1966	2.365332521686197
1967	2.4004869882818447
1968	2.633693501750114
1969	2.644772485162076
1970	2.8945670369806726
1971	2.945609496271496
1972	3.065073809161467
1973	3.0920407852686043
1974	3.0572819966519558
1975	3.2115050981585758
1976	3.161223558058134
1977	3.2498554253538274
1978	3.2719525186425202
1979	3.2935930604169834
1980	3.220210013696546
1981	3.146522599299954
1982	3.027819205600365
1983	3.014579211687719
1984	2.8949018414244407
1985	2.8846446507380916
1986	2.723786333891341
1987	2.7435702328412725
1988	2.7752244711611627
1989	2.7627453964388984
1990	2.8324455942778877
1991	2.850403287170902
1992	2.8199665195556234
1993	2.786181707502663
1994	2.8242276670217623
1995	2.7423527621366612
1996	2.7152640389590625
1997	2.7049155379698675
1998	2.6623040633084765
1999	2.6696088875361434
2000	2.644042002739309
2001	2.669304519859991
2002	2.944757266778268
2003	2.8800486988281846
2004	2.8814487901384873
2005	2.889697154162228
2006	2.7094810531121594
2007	2.5177294171359
2008	2.6492162532339063
2009	2.571906863491097
2010	2.600213057373307
2011	2.6346066047785723
2012	2.6431288997108506
2013	2.443159336478466
2014	2.4471161162684525
2015	2.5119768680566126
2016	2.5140770050220667
2017	2.5140770050220667
2018	2.5140770050220667
2019	2.5140770050220667
2020	2.5140770050220667
2021	2.5140770050220667