Year	% of land area
1961	1.715328467153285
1962	1.8613138686131385
1963	2.0072992700729926
1964	2.116788321167883
1965	2.2627737226277373
1966	2.3722627737226274
1967	2.4817518248175183
1968	2.5547445255474455
1969	2.737226277372263
1970	2.846715328467153
1971	2.9197080291970803
1972	3.065693430656934
1973	3.2116788321167884
1974	3.4671532846715327
1975	3.613138686131387
1976	4.014598540145985
1977	4.087591240875913
1978	4.160583941605839
1979	4.160583941605839
1980	4.2700729927007295
1981	4.306569343065694
1982	4.37956204379562
1983	4.416058394160584
1984	4.525547445255475
1985	4.525547445255475
1986	4.525547445255475
1987	4.525547445255475
1988	4.525547445255475
1989	4.562043795620438
1990	4.562043795620438
1991	4.562043795620438
1992	4.562043795620438
1993	4.562043795620438
1994	4.562043795620438
1995	4.562043795620438
1996	4.562043795620438
1997	4.452554744525548
1998	4.452554744525548
1999	4.452554744525548
2000	4.416058394160584
2001	4.416058394160584
2002	4.416058394160584
2003	4.416058394160584
2004	4.416058394160584
2005	4.416058394160584
2006	4.416058394160584
2007	4.37956204379562
2008	3.1751824817518246
2009	3.1751824817518246
2010	2.5547445255474455
2011	2.7007299270072993
2012	2.8065693430656933
2013	2.8905109489051095
2014	2.934306569343066
2015	2.9562043795620436
2016	3.0364963503649633
2017	3.072992700729927
2018	3.0895620437956204
2019	3.1386861313868613
2020	3.210036496350365
2021	3.1981751824817515