There exists no equation as several variables would be factored in to the equation.
However, if your goal was to increase your squat and you remained plateaued for a year, you were doing something wrong.--(Given your stats) Obviously at some point you may reach a max, but that is not your issue given what info you gave.
Small incremental increases as well as periodization is critical once you get into bigger weights. You can't consistantly go heavier and you have to make those steps smaller. Add a washer. Add a lb. Add a 2.5. Add a rep.........
The old story of the guy going out every day and picking up the calf and carrying it around has merit. By the day the calf grew little, but over the year the progress was obvious.
I don't understand this. You're the fourth person in the last week to ask a question like this.
The progress you make can be determined by you only. This means there are no equations and really not even any educated guesses that anyone on the Internet can make for you to determine what your progress should look like.
Use your past experiences (progress, training level, etc) to set your goals. It's not that difficult.
I'm not a complete beginner, since I was an infamous "1/4 squat" guy in high school, but I've made some really great gains in the last 4 months since I started eating and lifting right. Still pretty pathetic, but I'm improving. The first time I did ATG squats was in Dec 2005, and I used a weight of 155 lbs for reps. Yesterday I did sets of 7 @ 235, ass to grass. I'm hoping that by the time December rolls around again, I'm using 275, which would be about +120 difference in a single year.
Ive noticed that when someone starts a compound lift like squats once they get their form down and into a heavy workout for a while, the gains come fast, its not the amount of weight, its how you lift it!
The first thing I ever squatted was 50kg. A few months later I went up to 100kg. I've gone back down to squatting numbers I can actually handle without fucking up the technique. What can I say? I've got a technique fixation.