WeWillGetIn:
The schools will almost surely not dig into this information. It's pretty much an honor policy when it comes to reporting on your achievements and KPIs about your company or any companies with which you have worked. The idea behind presenting KPIs is more to give the schools a sense for the scale and scope of your accomplishments. You are not being evaluated based on the size, performance, etc. of your company unless you were directly responsible for achieving those KPIs.
I would also not make guesses about facts just to have something to input. If you have some real sense for a KPI, estimate it. If you do not, don't include it or list it as N/A (or something like that.)
Hope that helps,
Admissionado