url="http://islands.unep.ch/Tiarea.htm";

w1=Import[url];

Head[w1]

StringLength[w1]

w2=StringSplit[w1,"\n"];

w2[[20]]

FullForm[w2[[20]]]

StringMatchQ[w2[[20]],"*sq.km.*"]

w3=Select[w2,StringMatchQ[#,"*sq.km.*"]&];

w4=Rest[w3];

w5=Map[StringSplit,w4];

w6=w5[[All,1]];

w7=ToExpression[w6];

w8=Round[10*w7];

w9=Union[w8];

w10=Map[(ToString[#]//Characters//First//ToExpression)&,w9];

Histogram[w10]