Year	% of land area
1961	3.059836808703536
1962	3.0825022665457844
1963	3.093834995466908
1964	3.1165004533091567
1965	3.127833182230281
1966	3.150498640072529
1967	3.1618313689936532
1968	3.184496826835902
1969	3.1958295557570264
1970	3.218495013599275
1971	3.229827742520399
1972	3.252493200362647
1973	3.2638259292837715
1974	3.28649138712602
1975	3.297824116047144
1976	3.3204895738893923
1977	3.3318223028105165
1978	3.3544877606527654
1979	3.3658204895738897
1980	3.388485947416138
1981	3.293291024478694
1982	3.3556210335448777
1983	3.445149592021759
1984	2.4036718041704446
1985	3.13689936536718
1986	3.13689936536718
1987	3.4338168631006347
1988	3.4904805077062555
1989	3.3182230281051677
1990	2.0308250226654576
1991	1.6931097008159566
1992	2.943109700815956
1993	2.5951949229374436
1994	2.3912058023572076
1995	2.8558476881233004
1996	2.0398912058023573
1997	2.1192203082502266
1998	2.1532184950135993
1999	2.1532184950135993
2000	2.1532184950135993
2001	2.175883952855848
2002	2.20988213961922
2003	2.0058930190389845
2004	2.368540344514959
2005	2.096554850407978
2006	2.1532184950135993
2007	1.5899818676337263
2008	1.694242973708069
2009	2.26177066906961
2010	2.0004505519261095
2011	1.9779229556206355
2012	2.4442441991439514
2013	2.601937373282271
2014	2.6751520612750617
2015	2.567019599008786
2016	2.672448749718405
2017	2.106330254561838
2018	2.264023428700158
2019	2.4190823704304343
2020	2.319976574993806
2021	2.243394823974593