Year	% of land area
1961	26.204379562043794
1962	26.43845960231563
1963	26.69015857034986
1964	26.977095393908883
1965	27.241379310344826
1966	27.510697206141455
1967	27.719607349609866
1968	27.91593254467657
1969	28.122325698464635
1970	28.328718852252706
1971	28.537628995721114
1972	28.744022149509185
1973	28.947898313616914
1974	29.44626227032469
1975	29.95721117543418
1976	30.465643090863324
1977	30.94890510948905
1978	31.45985401459854
1979	31.94311603322426
1980	32.451547948653406
1981	32.965013843443245
1982	33.262018625723634
1983	33.56154039768437
1984	33.86106216964511
1985	34.160583941605836
1986	34.485275610369996
1987	34.78479738233074
1988	35.084319154291464
1989	35.383840926252205
1990	35.58915177447772
1991	35.791945633022905
1992	36.16949408507425
1993	36.16949408507425
1994	36.5470425371256
1995	36.92459098917694
1996	36.92459098917694
1997	36.92459098917694
1998	37.55635539894286
1999	37.810571356657434
2000	37.99431160332243
2001	38.22084067455324
2002	38.49267556003021
2003	38.67389881701485
2004	38.90042788824566
2005	39.126956959476466
2006	39.35348603070727
2007	39.58001510193808
2008	39.82416310093129
2009	40.07837905864586
2010	40.38545179964762
2011	40.75544928265794
2012	41.35449282657941
2013	41.66659954694186
2014	42.11714069972313
2015	42.63312358419331
2016	42.119657689403475
2017	42.09197080291971
2018	42.30339793606846
2019	42.308431915429146
2020	42.308431915429146
2021	42.308431915429146