Yes, I saw that as well.... strikes me as a bit odd but since exact figures are lacking it's tough to determine how much more than 50% is a majority. I guess they must also buy a lot of their fuel at the outstations.
And the fuel argument is a bit daft to begin with, just look at the annual reports to see that the fuel bill is comparable with other airlines, even more than for some... although also a bit difficult to compare one-on-one because nobody has the same business model with mostly rather fuel efficient wide-bodies.

This is a bit of other, probably more independent, research that's worth reading as well: http://dspace.mit.edu/bitstream/hand...pdf?sequence=1