Quick and dirty calculation based on AEA 2002 figures:
132.4 747-400s in the fleet, flying 526,884 million kms/year equals 3,98 mill km per aircraft.
Assume 400 seats/ac that's 1592 mill seat/km
AEA longhaul pax loadfactor was 79.2%, that's 1262 mill pax-km
Average longhaul yield was 6.34 cents per km
That gives total passenger revenue per ac for the year of more or less exactly $80m.
Freight and mail revenue add roughly 15% brings the total to $92m
(really dirty now) depreciate the ac at $10m pa over 20 years...
That means ac ownership costs are just over 10% of the total - sounds about right?