Year	% of land area
1961	38.72378117358777
1962	38.73309602754927
1963	38.769000555546356
1964	38.77162565075369
1965	38.77924689490402
1966	38.80096744073244
1967	38.81087505812786
1968	38.87667179929233
1969	38.91740311525129
1970	38.930909653495476
1971	39.00724911573456
1972	39.03904663993953
1973	39.05505125265521
1974	39.04817601273548
1975	39.099223957464226
1976	39.13098021707817
1977	39.15079612307727
1978	39.22328507835603
1979	39.24390547626535
1980	39.28679759758391
1981	39.33714185449189
1982	39.37762050007979
1983	39.435247525859225
1984	39.47111092838324
1985	39.68531748489916
1986	39.88605938733876
1987	39.987933468180294
1988	40.19760946499129
1989	40.33526226499786
1990	40.418420900090105
1991	40.54735986714197
1992	40.76605727533579
1993	40.24479860624741
1994	40.51482173454299
1995	40.786488109546056
1996	40.94938995590156
1997	41.11992387304762
1998	41.22096756157359
1999	41.426745799313736
2000	41.565793880450215
2001	41.72005721546465
2002	41.822751793371246
2003	42.07581129939374
2004	41.882649825956904
2005	42.22635836882274
2006	42.340778561974886
2007	42.50852979766131
2008	42.62895954291312
2009	42.84404968753073
2010	43.01318870715297
2011	43.176228717640505
2012	43.19203415116846
2013	43.38341200242183
2014	43.49780113503485
2015	43.61880292412736
2016	43.71956632510388
2017	43.81730406092512
2018	43.95388239774315
2019	44.02569046299666
2020	44.08391877079165
2021	44.12827715147594