Year	% of land area
1961	38.72432368714844
1962	38.73363872253435
1963	38.769543949840056
1964	38.772169096176086
1965	38.77979048876456
1966	38.801511457641716
1967	38.81141926800674
1968	38.87721729068724
1969	38.91794939996564
1970	38.93145620127522
1971	39.00779715036978
1972	39.03959529389169
1973	39.05560021832749
1974	39.048724853794866
1975	39.099773802108324
1976	39.13153068025647
1977	39.15134697222091
1978	39.223837339407055
1979	39.244458138951245
1980	39.28735109570333
1981	39.33769633319418
1982	39.37813342470281
1983	39.43576157291563
1984	39.471625673970934
1985	39.68583640270618
1986	39.886582215106614
1987	39.98845828020584
1988	40.19818070349615
1989	40.33583618464228
1990	40.41903878196536
1991	40.54798026043265
1992	40.7666819283166
1993	40.24541310638542
1994	40.51544149407051
1995	40.787113160469495
1996	40.950018179754174
1997	41.12055541848346
1998	41.22160107509312
1999	41.427383320889575
2000	41.56643411034228
2001	41.720700450028836
2002	41.823397028174405
2003	42.076461463176564
2004	41.883292186180924
2005	42.22700738056014
2006	42.341429788614995
2007	42.50922634760842
2008	42.62965842497453
2009	42.844756939627665
2010	43.01392025070794
2011	43.17700127751732
2012	43.19280300777093
2013	43.38418245225236
2014	43.49857378889563
2015	43.61957790609067
2016	43.72034324696869
2017	43.818082865076285
2018	43.95466383115902
2019	44.0264732786439
2020	44.084702709118716
2021	44.1290619439056