Year % of land area 1961 1.1195512962063332 1962 1.1416331758159255 1963 1.1504659276597624 1964 1.2145033785275803 1965 1.2145033785275803 1966 1.2078788146447026 1967 1.2542507618248466 1968 1.296206333083072 1969 1.3403700923022568 1970 1.3779092876385637 1971 1.4309057987015854 1972 1.452987678311178 1973 1.4949432495694033 1974 1.5545643245153027 1975 1.6031444596564062 1976 1.6451000309146313 1977 1.6738064744071017 1978 1.7290111734310825 1979 1.7510930530406748 1980 1.759925804884512 1981 1.7731749326502673 1982 1.7555094289625934 1983 1.7488848650797157 1984 1.7820076844941042 1985 1.828379631674248 1986 1.8902088945811066 1987 1.903458022346862 1988 1.9586627213708432 1989 2.0006182926290688 1990 2.049198427770172 1991 2.060239367574968 1992 2.080113059223601 1993 2.144150510091419 1994 2.1596078258181337 1995 2.1949388331934814 1996 2.243518968334585 1997 2.258976284061299 1998 2.349511990460628 1999 2.3870511857969348 2000 2.40250850152365 2001 2.413549441328446 2002 2.4356313209380382 2003 2.4466722607428344 2004 2.4797950801572233 2005 2.5018769597668156 2006 2.5416243430640817 2007 2.676323808682595 2008 2.7491940113942497 2009 2.797774146535353 2010 2.797774146535353 2011 2.8397297177935785 2012 2.8397297177935785 2013 2.8397297177935785 2014 2.8816852890518043 2015 2.9192244843881108 2016 2.9324736121538666 2017 3.1025040851477277 2018 3.1025040851477277 2019 3.1002958971867685 2020 3.1312105286401977 2021 3.1819988517422604