Wobbly,
AFAIK, they are one of the few airlines which do not hedge fuel, nor do they add surcharges for it. They have quite a few press releases about this on their website, and have frequently criticised other airlines for imposing fuel surcharges when the price goes up, and then pocketing the difference when the price goes down. I don't think TOM surcharge either.
I know the 737-800 drinks a similar amound to a 737-200 for the same journey, but carries 189 instead of 132 (iirc). Not sure where the other 73- models would compare on this, but
afaik, the -200 was a thirsty monster, so -300s, -500s should be quite a bit better, but still a little way off the Next generation models. Sorry for using such vague terms, if anyone has useful reference sources, please pass them on!