79.99
This is depressing...
P.S.: Mars Arkadios, wtf man? Your nation is 2 days old and you're already almost above my strength range.
This is even more depressing...
Just a small contribution.
A plug in formula for infra jumps.
x equals:
(amount of infra before jump*(new upkeep - old upkeep))
((pop. per infra lvl. * income per cit.) - new upkeep)
Edit: this is basically a rearrangement of Cheesejaguar's formula.