Year	% of land area
1961	3.6506469500924212
1962	3.789279112754159
1963	4.066543438077634
1964	4.11275415896488
1965	4.066543438077634
1966	4.11275415896488
1967	4.066543438077634
1968	3.9279112754158962
1969	3.9741219963031424
1970	3.8817005545286505
1971	3.9279112754158962
1972	3.9741219963031424
1973	4.020332717190389
1974	4.066543438077634
1975	3.9741219963031424
1976	4.020332717190389
1977	4.066543438077634
1978	4.066543438077634
1979	4.066543438077634
1980	4.066543438077634
1981	4.297597042513863
1982	4.390018484288355
1983	4.251386321626617
1984	4.205175600739372
1985	4.297597042513863
1986	4.1589648798521255
1987	4.11275415896488
1988	4.11275415896488
1989	4.11275415896488
1990	4.066543438077634
1991	3.9741219963031424
1992	3.9279112754158962
1993	3.9279112754158962
1994	3.9279112754158962
1995	3.8354898336414047
1996	3.8354898336414047
1997	3.8354898336414047
1998	3.8817005545286505
1999	3.9279112754158962
2000	3.9741219963031424
2001	3.8817005545286505
2002	3.8817005545286505
2003	3.9741219963031424
2004	3.211645101663586
2005	3.211645101663586
2006	3.2255083179297594
2007	3.4796672828096122
2008	3.5720887245841033
2009	3.618299445471349
2010	3.5720887245841033
2011	3.7569316081330872
2012	4.22365988909427
2013	4.366913123844732
2014	4.491682070240296
2015	4.468576709796673
2016	4.482439926062846
2017	4.436229205175601
2018	4.611829944547135
2019	4.639556377079482
2020	4.685767097966728
2021	4.736598890942699