That seems to be ignoring commuters. Suburbanites often commute into the city, raising employment numbers while reducing the number of employed locals.
For instance (from wikipedia):
Manhattan is the economic engine of New York City, with its 2.3 million workers drawn from the entire New York metropolitan area accounting for almost two-thirds of all jobs in New York City.[139] Manhattan's daytime population swells to 2.87 million, with commuters adding a net 1.34 million people to the population. This commuter influx of 1.46 million workers coming into Manhattan was the largest of any other county or city in the country, and was more than triple the 480,000 commuters who headed into second-ranked Washington, D.C.[140][141]
Based on your method, Manhatten has ~200% employment rate. (Yes I noticed the numbers there seem to conflict slightly, but it gets the point across.)
For instance (from wikipedia):
Manhattan is the economic engine of New York City, with its 2.3 million workers drawn from the entire New York metropolitan area accounting for almost two-thirds of all jobs in New York City.[139] Manhattan's daytime population swells to 2.87 million, with commuters adding a net 1.34 million people to the population. This commuter influx of 1.46 million workers coming into Manhattan was the largest of any other county or city in the country, and was more than triple the 480,000 commuters who headed into second-ranked Washington, D.C.[140][141]
Based on your method, Manhatten has ~200% employment rate. (Yes I noticed the numbers there seem to conflict slightly, but it gets the point across.)