Year % of land area 1961 11.049601905560088 1962 11.058423943009638 1963 11.071656999183961 1964 11.084890055358285 1965 11.093712092807834 1966 11.102534130257382 1967 11.115767186431706 1968 11.137822280055579 1969 11.159877373679452 1970 11.181932467303323 1971 11.203987560927196 1972 11.226042654551069 1973 11.248097748174942 1974 11.270152841798813 1975 11.270152841798813 1976 11.292207935422686 1977 11.30544099159701 1978 11.314263029046558 1979 11.314263029046558 1980 11.33631812267043 1981 11.358373216294302 1982 11.367195253743851 1983 11.380428309918175 1984 11.402483403542048 1985 11.424538497165921 1986 11.446593590789792 1987 11.446593590789792 1988 11.446593590789792 1989 11.446593590789792 1990 11.451004609514568 1991 11.459826646964116 1992 11.468648684413665 1993 11.468648684413665 1994 11.468648684413665 1995 11.380428309918175 1996 11.380428309918175 1997 11.33631812267043 1998 11.33631812267043 1999 11.292207935422686 2000 11.292207935422686 2001 11.270152841798813 2002 11.270152841798813 2003 11.270152841798813 2004 11.270152841798813 2005 11.270152841798813 2006 11.286032509208002 2007 11.314263029046558 2008 11.33631812267043 2009 11.859906045301162 2010 12.540085132661389 2011 13.072495092741669 2012 13.62387243333848 2013 13.863831851966212 2014 14.225094285525241 2015 14.31375576189321 2016 14.411680377583203 2017 14.697955492821066 2018 14.81837630400741 2019 14.92247634591209 2020 14.951147967623122 2021 14.952471273240556