Year	% of land area
1961	5.588904988615194
1962	5.692403229145104
1963	5.795901469675015
1964	5.899399710204927
1965	6.0028979507348375
1966	6.106396191264748
1967	6.20989443179466
1968	6.416890912854481
1969	6.520389153384393
1970	6.520389153384393
1971	6.582488097702339
1972	6.623887393914303
1973	7.037880356033948
1974	7.037880356033948
1975	7.037880356033948
1976	7.244876837093769
1977	7.244876837093769
1978	7.244876837093769
1979	7.244876837093769
1980	7.244876837093769
1981	7.244876837093769
1982	7.34837507762368
1983	7.34837507762368
1984	7.34837507762368
1985	7.34837507762368
1986	7.493272614365557
1987	9.232043055268061
1988	9.232043055268061
1989	9.232043055268061
1990	9.232043055268061
1991	9.232043055268061
1992	9.232043055268061
1993	9.232043055268061
1994	9.232043055268061
1995	9.232043055268061
1996	9.107845166632167
1997	9.107845166632167
1998	9.107845166632167
1999	8.693852204512522
2000	8.693852204512522
2001	8.693852204512522
2002	8.693852204512522
2003	8.652452908300559
2004	8.27985924239288
2005	8.27985924239288
2006	8.27985924239288
2007	8.27985924239288
2008	8.27985924239288
2009	8.27985924239288
2010	8.27985924239288
2011	8.27985924239288
2012	7.34837507762368
2013	7.34837507762368
2014	7.34837507762368
2015	7.34837507762368
2016	7.34837507762368
2017	7.34837507762368
2018	7.34837507762368
2019	7.468809829374513
2020	7.468809829374513
2021	7.468809829374513