Year	% of land area
1961	12.28467815049864
1962	12.307343608340888
1963	12.318676337262012
1964	12.36400725294651
1965	12.375339981867633
1966	12.398005439709882
1967	12.432003626473255
1968	12.454669084315503
1969	12.466001813236627
1970	12.511332728921124
1971	12.52266545784225
1972	12.567996373526746
1973	12.57932910244787
1974	12.624660018132367
1975	12.63599274705349
1976	12.65865820489574
1977	12.669990933816862
1978	12.71532184950136
1979	12.749320036264733
1980	12.77198549410698
1981	12.665457842248411
1982	12.739120580235722
1983	12.896645512239346
1984	11.900498640072529
1985	12.667724388032639
1986	12.758386219401633
1987	13.100634632819583
1988	13.202629193109699
1989	13.030371713508613
1990	11.7883046237534
1991	11.450589301903898
1992	12.700589301903896
1993	12.352674524025385
1994	12.14868540344515
1995	12.624660018132367
1996	11.910698096101541
1997	12.024025385312784
1998	12.080689029918403
1999	12.092021758839529
2000	12.114687216681777
2001	11.58204895738894
2002	11.616047144152313
2003	11.389392565729828
2004	11.752039891205802
2005	11.48005439709882
2006	11.536718041704443
2007	10.916817769718948
2008	11.021078875793291
2009	11.545393106555531
2010	11.289704888488398
2011	11.293084027934219
2012	11.769542689795
2013	11.901329128182022
2014	11.984681234512278
2015	11.897949988736203
2016	12.006758278891642
2017	11.342644739806262
2018	11.509348952466771
2019	11.67308601932563
2020	11.588620852760322
2021	11.521048719508075