Year	% of land area
1961	11.985939113483528
1962	11.808826278356205
1963	11.96353310670953
1964	11.892750870584537
1965	11.8573845806507
1966	11.803590301890182
1967	11.74014063976239
1968	12.103232710629154
1969	12.561835833764972
1970	12.537504267679447
1971	12.508317423100666
1972	12.482220301199408
1973	12.461640541222307
1974	12.436481370848158
1975	12.443212552395627
1976	12.449833386704615
1977	12.469695889631575
1978	12.60669198620836
1979	12.622140599595996
1980	12.637589212983633
1981	12.653148173609752
1982	12.60956101440892
1983	12.620595738257231
1984	12.631630462105543
1985	12.642665185953854
1986	12.653755083421407
1987	12.539214649875937
1988	12.536290448056134
1989	12.532483468328467
1990	12.526800585546587
1991	12.524064520251036
1992	12.433170953693667
1993	12.35681066466335
1994	12.309306178496369
1995	12.300925305733577
1996	12.141804587840927
1997	12.06257527061005
1998	12.016670819401075
1999	11.937441502170199
2000	11.934278648802454
2001	11.934775130293291
2002	11.782741464876361
2003	11.64048848482896
2004	11.499906992467382
2005	11.357676078264019
2006	11.215445164060654
2007	11.069573385591136
2008	10.981620779344677
2009	10.884812199636682
2010	10.788003619928688
2011	10.691029413908105
2012	10.62999611771923
2013	10.673881569678104
2014	10.71776702163698
2015	10.76170216148963
2016	10.80553240467764
2017	10.83450596762646
2018	10.844498755152635
2019	10.842179986776395
2020	10.819378764410041
2021	10.927419638101192