Year	% of land area
1961	4.355659519631071
1962	4.420649431727764
1963	4.492594599827955
1964	4.565875177080818
1965	4.617344071506709
1966	4.702253836797421
1967	4.779373715364216
1968	4.905347312099586
1969	4.941347717173696
1970	4.935060165746533
1971	5.007450470230948
1972	5.1282493564997145
1973	5.219459064701686
1974	5.29493877149035
1975	5.393198327177468
1976	5.579318085076194
1977	5.760391010628265
1978	5.9350650599352655
1979	6.093586100293291
1980	6.270319359844735
1981	6.349098759228996
1982	6.429219592374536
1983	6.5310409756569845
1984	6.6015412235441016
1985	6.697537237318946
1986	6.6590335351485015
1987	6.662279309521703
1988	6.633574075959735
1989	6.627404040420902
1990	6.623008993489277
1991	6.605092831082318
1992	6.575603038968078
1993	6.535658035966168
1994	6.501433071313034
1995	6.5021169170298725
1996	6.547448265040572
1997	6.622188317422375
1998	6.7016559282767325
1999	6.76464395563608
2000	6.809972017581942
2001	6.858147364408437
2002	6.901806893169253
2003	7.086038051744443
2004	7.192608354948775
2005	7.337749304024813
2006	7.474434915206627
2007	7.607526842766735
2008	7.55094036767554
2009	7.513812216280385
2010	7.743455882557845
2011	7.796564686157005
2012	7.882913563703128
2013	7.896085111506374
2014	7.889359649900251
2015	7.98914490490861
2016	7.968900482440127
2017	7.931858893711806
2018	7.970749606601185
2019	7.99769271818528
2020	8.157254720168552
2021	8.22655654589147