Anti / pro squat is a function of suspension design and , if you are anywhere near design ride height / nothing is severly worn , should remain constant. All the rubber in a bushing would need to be gone not slightly compressed for example.

Anti / pro squat for the rear and anti / pro dive in the front is measured in % as a function of suspension design not how many inches things move because the more dynamic load applied to the suspension the more action that will occur.

Spring rate ( lb per inch of compression ) plays a factor in how far the rear will drop however, spring rate does not change over time.

Look at some vids of your type of car accelerating and compare to yours.