Schools or stadiums?

Being the hopelessly backwards fellow I am, I still haven't got around to purchase improvements. I'm just wondering what will generate the most cash, a stadium or the school/university route?

 

First up buy a Harbour, there is no better option for the first one.

After that I've been buying factories, they make infra cheaper and the more infra you buy the more people you have, the more people the more taxpayers and the more money you have the more infra you can buy.

Its an endless cycle to get you to the coveted 1000 infra as quickly as possible, after factoies go for schools and universities to get a tech discount or banks to increase income and therefore taxes. Once you hit 1000 infra and 75 tech you are in the realm of nuke buying.