Year	% of land area
1993	39.545925155925154
1994	39.54370062370062
1995	39.54147609147609
1996	39.53925155925156
1997	39.53702702702703
1998	39.5348024948025
1999	39.53257796257796
2000	39.53035343035343
2001	39.56465696465696
2002	39.598960498960494
2003	39.6250259821243
2004	39.667567567567566
2005	39.7018711018711
2006	39.73617463617463
2007	39.77047817047817
2008	39.8047817047817
2009	39.847369515491785
2010	39.88085088686032
2011	39.899309599068374
2012	39.91528031941441
2013	39.93125103976044
2014	39.953868552412644
2015	39.96817936025956
2016	40.00353577371049
2017	40.056156405990016
2018	40.056156405990016
2019	40.056156405990016
2020	40.056156405990016
2021	40.056156405990016