Consider Figure 8.9. Your classmate looks at that chart and says, Apartment construction slowed down years before

Question:

Consider Figure 8.9. Your classmate looks at that chart and says, “Apartment construction slowed down years before rent control was passed, and after rent control was passed, more apartments were built. Rent control didn’t cut the number of new apartments, it raised it. This proves that rent control works.” What is wrong with this argument?