Year	% of land area
1961	2.344360510549622
1962	2.4702613527828428
1963	2.7003559954849354
1964	2.9044021880698097
1965	2.8696709212468527
1966	3.0606928887731177
1967	3.156203872536251
1968	3.312494573239559
1969	3.3559086567682557
1970	3.3819571068854732
1971	3.377615698532604
1972	3.364591473473995
1973	3.3342016150039075
1974	3.325518798298168
1975	3.29512893982808
1976	3.2907875314752104
1977	3.269080489710862
1978	3.208300772770687
1979	2.8826951463054615
1980	2.878353737952592
1981	2.865329512893983
1982	2.839281062776765
1983	2.826256837718156
1984	2.77415993748372
1985	2.7654771207779807
1986	2.7481114873665016
1987	2.6308934618390207
1988	2.6048450117218023
1989	2.594288205798997
1990	2.5768476128188356
1991	2.6017606554519306
1992	2.62790900374793
1993	2.61483482959993
1994	2.557622761535445
1995	2.483768355919648
1996	2.3745207389334264
1997	2.404914390275781
1998	2.2561958273443965
1999	2.2343205574912894
2000	2.2941970310391366
2001	2.137477689260372
2002	2.10118762778962
2003	2.0221787345075013
2004	1.865217391304348
2005	2.2175841377511087
2006	2.039307765892686
2007	2.0053068859019527
2008	2.0139190952588084
2009	1.9994783969399288
2010	2.0126059552271243
2011	1.9290089933527395
2012	1.9389618294061388
2013	1.9214885014998044
2014	1.847183588317107
2015	1.847183588317107
2016	1.816759388038943
2017	1.8037204450625868
2018	1.9123783031988872
2019	1.7906815020862308
2020	1.7515646731571628
2021	1.7428720445062587