Year	% of land area
1961	44.91248117176544
1962	44.91248117176544
1963	45.43188074585779
1964	45.43188074585779
1965	45.951280319950136
1966	45.951280319950136
1967	46.47067989404249
1968	47.35365916999948
1969	46.24214408144186
1970	46.03957824754584
1971	46.46548589830156
1972	46.46548589830156
1973	46.72518568534774
1974	46.98488547239391
1975	46.98488547239391
1976	46.97969147665299
1977	45.93569833272736
1978	45.930504336986445
1979	45.92531034124552
1980	45.920116345504596
1981	45.91492234976367
1982	45.90972835402275
1983	45.90453435828183
1984	45.899340362540904
1985	45.89414636679998
1986	45.88375837531814
1987	45.87337038383629
1988	45.86298239235444
1989	45.847400405131665
1990	46.06554822625045
1991	45.2345089077027
1992	45.603282605308266
1993	45.80065444346336
1994	46.30447203033293
1995	45.78507245624059
1996	46.26292006440555
1997	44.813795252687896
1998	43.5776242663481
1999	47.327689191294866
2000	46.88619955331637
2001	45.70196852438581
2002	45.447462733080556
2003	44.83457123565159
2004	45.12024100140238
2005	45.58250662234457
2006	44.09702384044045
2007	44.164545785072455
2008	48.17431049706539
2009	48.18989248428816
2010	48.18989248428816
2011	46.564171817379105
2012	46.564171817379105
2013	46.57975380460188
2014	46.60052978756558
2015	48.44959227133433
2016	48.2418324416974
2017	48.42362229262972
2018	48.60541214356204
2019	48.79758998597622
2020	48.979379836908535
2021	49.400093491923336