While 4 different covers to this issue exist, the IG-88 cover is the rarest, comprising of only 10% of the total print run, and randomly sent out to Nintendo Power subscribers.
The ratios are as follows for this issue:
Stormtrooper Cover - 40%
Boba Fett Cover - 25%
Dash Rendar Cover - 25%
IG-88 Cover - 10%
This information can found inside the magazine itself.