Today's US Demography factoid
From Richard Greene:
Detroit has not had the largest peak-to-trough decline in percentage terms among large American cities
Although it is getting close. Detroit has lost about 58% of its 1950 population; St. Louis has lost about 59%. And Detroit's population is much larger than it was in 1900; St. Louis has lost about 30% of its population since 1900 (just prior to the 1904 World's Fair, when 20 million people visited St. Louis.
Awesome. (Worth noting, though, that St. Louis has been surrounded by suburban communities, and Missouri's law (apparently) makes annexation very difficult, so the city limits of St. Louis have been essentially unchanged. I suspect Detroit has expanded grographically.)