Year	% of land area
1961	9.388951453355654
1962	9.590473291736417
1963	9.970689392786486
1964	10.159853903515446
1965	10.644772485162076
1966	10.677613757418962
1967	10.871039415614062
1968	11.262517120681784
1969	11.431867295693197
1970	11.824714655303607
1971	12.049246690001523
1972	12.418292497336783
1973	12.664404200273932
1974	12.848790138487292
1975	13.252594734439201
1976	13.512768224014609
1977	13.911855120986152
1978	14.396591082027088
1979	14.728686653477402
1980	14.96575863643281
1981	15.354710089788465
1982	15.546461725764724
1983	15.843676761527925
1984	15.876183229341043
1985	16.483792421244864
1986	17.40952670826358
1987	18.485466443463704
1988	19.43022371024197
1989	20.458682087962256
1990	20.564906406939585
1991	20.68026175620149
1992	20.716785877339827
1993	20.975194034393546
1994	21.27803987216558
1995	21.20225232080353
1996	21.187338304672043
1997	21.180033480444376
1998	21.137422005782984
1999	21.14472683001065
2000	21.11915994521382
2001	21.1444224623345
2002	21.41987520925278
2003	21.65953431745549
2004	21.706589560188707
2005	21.71483792421245
2006	21.534621823162382
2007	21.632019479531273
2008	21.76350631562928
2009	21.97534621823162
2010	22.4906406939583
2011	22.920712220362198
2012	23.829554101354436
2013	24.52990412418201
2014	24.620301323999392
2015	26.084218535991475
2016	26.08735352305585
2017	26.08735352305585
2018	26.08735352305585
2019	26.08735352305585
2020	26.08735352305585
2021	26.08735352305585