Year	% of land area
1990	44.617394550205304
1991	44.083613288540505
1992	43.5498320268757
1993	43.0160507652109
1994	42.4822695035461
1995	41.9484882418813
1996	41.4147069802165
1997	40.880925718551694
1998	40.347144456886895
1999	39.813363195222095
2000	39.279581933557296
2001	38.82549458753266
2002	38.371407241508024
2003	37.91731989548339
2004	37.46323254945875
2005	37.009145203434116
2006	36.55505785740949
2007	36.10097051138485
2008	35.64688316536021
2009	35.19279581933557
2010	34.738708473310936
2011	34.48338932437477
2012	34.2280701754386
2013	33.97275102650242
2014	33.717431877566256
2015	33.46211272863008
2016	33.3538633818589
2017	33.24561403508772
2018	33.13736468831653
2019	33.02911534154535
2020	32.92086599477417
2021	32.81261664800299