Stephen Curry broke the NBA record for the most 3-pointers in a season two years ago by such a wide margin that it already seems like a statistical error instead of an outlier. Nobody had ever made more than 286 threes in a season when Curry came along and made 402. A half-century earlier, when Roger Bannister first ran a mile in less than four minutes, he shaved less than 1% off the existing record. Curry was 41% above the nearest competition.

It helps to have that recent context to understand the NBA’s latest calculator...