Year	% of land area
1990	33.013661767749944
1991	33.79523908093562
1992	34.5768163941213
1993	35.35839370730697
1994	36.13997102049266
1995	36.92154833367833
1996	37.703125646864
1997	38.484702960049674
1998	39.26628027323535
1999	40.047857586421024
2000	40.82943489960671
2001	41.03777685779341
2002	41.246118815980125
2003	41.45446077416684
2004	41.66280273235355
2005	41.87114469054026
2006	42.07948664872696
2007	42.28782860691368
2008	42.49617056510039
2009	42.7045125232871
2010	42.912854481473815
2011	43.03924653280894
2012	43.16563858414407
2013	43.2920306354792
2014	43.418422686814324
2015	43.54481473814945
2016	43.71227489132685
2017	43.879735044504244
2018	44.047195197681646
2019	44.93930277082325
2020	45.10950747932928
2021	45.27971218783531