Year	% of land area
1961	2.510422422020192
1962	2.444120749409815
1963	2.424029333467276
1964	2.4330704706414186
1965	2.5938017981817265
1966	2.6952634486915468
1967	2.7063137274599427
1968	2.6992817318800544
1969	2.7374554221708776
1970	2.7374554221708776
1971	2.747501130142147
1972	2.7374554221708776
1973	2.7354462805766238
1974	2.7193731478225924
1975	2.703300015068562
1976	2.6078657893415036
1977	2.510422422020192
1978	2.4059470591189913
1979	2.314531116580441
1980	2.2964488422321563
1981	2.317544828971822
1982	2.2916670852378322
1983	2.2750916670852375
1984	2.285659751871013
1985	2.315535687377568
1986	2.328595107740218
1987	2.29845798382641
1988	2.3205585413632024
1989	2.3064945502034253
1990	2.2944397006379025
1991	2.2773619970867447
1992	2.627233914310111
1993	2.628138028027525
1994	2.6246019388216384
1995	2.829875935506555
1996	2.722848962780652
1997	2.7916218795519616
1998	2.806389070269727
1999	3.007684966598021
2000	2.813802802752524
2001	2.8740770505801394
2002	2.949419860364659
2003	2.9192827364508513
2004	2.97855241348134
2005	2.5747149530363154
2006	2.616906926515646
2007	2.5757195238334423
2008	2.6540760460093424
2009	2.8971821789140586
2010	2.8861319001456627
2011	2.8208347983324127
2012	2.841930785072078
2013	2.720347581495806
2014	2.652257772866543
2015	2.8789764428148077
2016	2.799503139283741
2017	2.9252788186247427
2018	3.062936360440002
2019	3.23371339595158
2020	3.380380732332111
2021	3.091064342759556