Year	% of land area
1961	11.956521739130435
1962	12.055335968379447
1963	12.154150197628459
1964	12.25296442687747
1965	12.351778656126482
1966	12.450592885375494
1967	12.648221343873518
1968	12.648221343873518
1969	12.845849802371543
1970	12.845849802371543
1971	13.142292490118576
1972	13.636363636363635
1973	14.130434782608695
1974	16.798418972332016
1975	16.205533596837945
1976	16.106719367588934
1977	16.798418972332016
1978	17.490118577075098
1979	16.40316205533597
1980	15.711462450592887
1981	17.885375494071145
1982	19.960474308300398
1983	18.08300395256917
1984	16.699604743083004
1985	16.699604743083004
1986	17.490118577075098
1987	18.181818181818183
1988	19.66403162055336
1989	17.885375494071145
1990	18.478260869565215
1991	19.367588932806324
1992	16.007905138339922
1993	15.909090909090908
1994	17.786561264822133
1995	18.280632411067195
1996	18.774703557312254
1997	20.25691699604743
1998	21.245059288537547
1999	22.233201581027668
2000	23.122529644268774
2001	24.110671936758894
2002	25.09881422924901
2003	26.08695652173913
2004	26.976284584980238
2005	27.964426877470355
2006	28.952569169960473
2007	29.940711462450594
2008	36.75889328063241
2009	42.29249011857708
2010	44.466403162055336
2011	44.466403162055336
2012	44.466403162055336
2013	44.466403162055336
2014	44.466403162055336
2015	44.466403162055336
2016	44.466403162055336
2017	43.47826086956522
2018	43.47826086956522
2019	43.47826086956522
2020	43.47826086956522
2021	43.47826086956522