Bingo for the oxygen. Seems to be equally spread across the galaxy too, then, like all other combinations of atmosphere/size/type. Means not even conquering the whole galaxy will improve my situation... although less competition might help then
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What I think is strange that I didn't find ANY large planets - neither Gas, nor Rock or Ice. 10 systems scouted so far, not counting black holes and nebulae. That led me to the conclusion they have been left out completely, due to the usually equal distribution metinoned above. You are sure that there are more except homeplanets?
Well, good that there are at least some. Though, such an exclusive rarity doesn't really help...