That's not how rates work. If you lose 10% of your teachers a year, in ten years you'll have about 35% of your teachers left. As an economist, surely this is second nature to you.

As always, I agree with your work, but I wish you'd fact check and accept corrections.

I stopped sending your writing to my friends because there were too many gross errors, errors that don't affect your conclusions, I hasten to add!, but make it a painful read for the numerate or skeptical.