Year	% of land area
1961	24.692049272116463
1962	24.804031354983202
1963	24.916013437849944
1964	25.027995520716683
1965	25.139977603583425
1966	25.25195968645017
1967	25.457260171705858
1968	25.5692422545726
1969	25.587905935050394
1970	25.70921985815603
1971	25.82120194102277
1972	26.129152668906308
1973	26.5304217991788
1974	26.82904068682344
1975	26.95035460992908
1976	27.342291899962675
1977	27.930197835013065
1978	28.042179917879807
1979	28.14483016050765
1980	28.462112728630085
1981	28.6207540126913
1982	28.96603210153042
1983	29.10600970511385
1984	35.32101530421799
1985	35.32101530421799
1986	35.32101530421799
1987	35.32101530421799
1988	39.98693542366555
1989	39.98693542366555
1990	39.98693542366555
1991	39.98693542366555
1992	39.98693542366555
1993	41.82530795072788
1994	42.10526315789473
1995	42.10526315789473
1996	42.10526315789473
1997	42.68784994400896
1998	43.27043673012318
1999	43.8530235162374
2000	44.43561030235163
2001	45.01819708846585
2002	45.60078387458007
2003	46.1832773422919
2004	44.074281448301605
2005	42.57185516983949
2006	40.271101157148195
2007	41.50802538260545
2008	41.37737961926092
2009	40.77640910787607
2010	40.28742067935797
2011	40.07838745800672
2012	39.776035834266516
2013	39.40836132885405
2014	39.98600223964166
2015	41.65733482642777
2016	41.93542366554684
2017	42.213512504665914
2018	42.49160134378499
2019	42.76969018290407
2020	43.03844718178424
2021	43.03844718178424