Year	% of land area
1961	9.077919002131523
1962	9.077919002131523
1963	9.077919002131523
1964	9.077919002131523
1965	9.07712954922239
1966	9.07712954922239
1967	9.07712954922239
1968	9.611589168706086
1969	9.610010262887819
1970	8.839504223573064
1971	8.862398357937948
1972	8.820557353753848
1973	8.533985947738218
1974	7.717691639693693
1975	7.717691639693693
1976	7.716112733875424
1977	7.716112733875424
1978	7.716112733875424
1979	7.8566353517012715
1980	8.061893108076102
1981	7.714533828057156
1982	7.777690060787874
1983	7.896107997157969
1984	7.714533828057156
1985	7.712954922238889
1986	7.712954922238889
1987	7.501381542590985
1988	7.491118654772243
1989	7.57401121023131
1990	8.712402305202495
1991	9.546064577247968
1992	10.25262493092287
1993	10.251835478013737
1994	10.251046025104603
1995	11.040498934238572
1996	11.040498934238572
1997	11.040498934238572
1998	11.039709481329439
1999	11.039709481329439
2000	11.032604405147232
2001	11.028657140601563
2002	11.020762611510223
2003	11.09181337333228
2004	11.13523328333465
2005	11.14944343569906
2006	11.160495776426936
2007	11.782584668824505
2008	11.778637404278834
2009	11.762848346096156
2010	11.92073892792295
2011	12.315465382489934
2012	12.552301255230125
2013	13.262808873450698
2014	13.262808873450698
2015	13.262808873450698
2016	13.815425909844478
2017	13.973316491671273
2018	13.973316491671273
2019	13.973316491671273
2020	13.973316491671273
2021	13.973316491671273