at this rate

[at this rate] or [at that rate] {adv. phr.} At a speed like this or that; with progress like this or that.

John's father said that if John kept going at that rate he would never finish cutting the grass.

So Johnny has a whole dollar! At this rate he'll be a millionaire.

"Three 100's in the last four tests! At this rate you'll soon be teaching the subject," Tom said to Mary.