Daytime population change due to commuting: -659 [[-0.1%)

It's not that simple when it comes to Detroit. I think you have situation where there are more professional/highly-skilled jobs within Detroit than Detroiters are qualified for, and a relative lack of much-needed low-level/service industry jobs. So you have suburbanites streaming in for the higher paying jobs, and masses of Detroiters taking the bus out to the inner-ring suburbs to work in the many restaurants and retailers located on the main thoroughfares. "-659" doesn't accurately portray the situation.