There is no way to estimate that. There may be a month where you can't hit 90% and there may be a month where you PR 3 times on a lift.
A lot of variables go into how your feeling day by day. Stress, sleep, nutrition, mobility issues, your girlfriend broke up with you, etc. There is no way to tell how well your going to do.
The thing you want to make sure and NOT do is get a number in your head that you think your going to start missing. Every time you walk up to the bar you should be thinking you're going to make it. If you don't, then odds are you're probably going to miss it.