Year	% of land area
1990	30.142593199645297
1991	29.985950760072612
1992	29.418931115357715
1993	29.262785740925622
1994	29.116501142817516
1995	28.96030286927525
1996	28.80410459573298
1997	28.647906317297156
1998	28.491708043754883
1999	28.33550977021262
2000	28.17882886001923
2001	28.03858403647284
2002	27.898339212926444
2003	27.758352475566525
2004	27.421178911279
2005	27.281952448761004
2006	27.14249237917791
2007	27.003107644999186
2008	26.86418664121623
2009	26.724911478822047
2010	26.584841769186916
2011	26.41112716333859
2012	26.08096031380092
2013	25.90882096831664
2014	25.738063336990244
2015	25.56671565545159
2016	25.394202147655246
2017	25.225417011388906
2018	25.057583232497027
2019	24.88619695193643
2020	24.716839420153118
2021	24.54610684327684