It changes every year so its really unpredictable.
the minimum requirement is 70% if you're applying as a foreign national. but that's the minimum eligibility, not the closing aggregate. it also depends on what college you're applying to, and under what scheme (PTAP, self finance, open merit etc.).
For example, getting into Dow under open merit is harder than getting into SMC. Same goes for KEMU in Lahore versus FJMC.
It's ideal to have an aggregate above 90% if you're a local applying through open merit. And if through self finance, I would guess above 80%.
As a foreign, then it would be different. equivalency would have a 10-15% cutoff. so i would say after equivalency, have it it above 80% at least.