Year	% of land area
1961	37.03826793787951
1962	37.02303553995389
1963	37.429463611878504
1964	37.37130354707157
1965	37.19405382575521
1966	37.30137299295848
1967	37.083965131656385
1968	37.2556757991816
1969	37.92451654446129
1970	37.58040282768696
1971	37.62956193008329
1972	37.9411337058347
1973	37.85181646345263
1974	37.58455711803031
1975	37.35399400397427
1976	37.31937491777967
1977	37.45785126255807
1978	37.488316058409325
1979	37.89197460343837
1980	37.54162945114901
1981	37.565862811485225
1982	36.66853609732117
1983	36.33273096123355
1984	36.95102784066912
1985	37.03549841098394
1986	37.01126505064772
1987	37.34637780501146
1988	37.241135782979875
1989	36.84750225178411
1990	36.665973810018706
1991	36.643088242425925
1992	12.006174140739564
1993	11.8971536693288
1994	11.852058076616887
1995	11.810910076396105
1996	11.660871434940232
1997	11.69236665432284
1998	11.586752470278922
1999	11.520233633385386
2000	11.37530613082959
2001	11.286025724979414
2002	11.194412890372416
2003	11.101309964720679
2004	11.071917362048795
2005	11.027144742396388
2006	11.061491473469184
2007	10.978436505942884
2008	10.970299416099234
2009	10.969009992943695
2010	10.93494059226487
2011	10.924717983005563
2012	10.915588381771478
2013	10.926012295028475
2014	10.939665533912045
2015	10.944426186614548
2016	10.92744006459195
2017	10.916172828378826
2018	10.917192007236705
2019	10.911463754842245
2020	10.905120503248277
2021	10.922501223931073