Greater downtown is a combination of the traditional Loop, or central business district, and the adjoining Near North, West and South sides, collectively referred to by IDES as the “outer business district.”

Combined, those two areas added just under 16,000 jobs in the year ended March 31, rising 2.9 percent to a total of 557,635. That easily is the highest tally since at least 1991, when IDES changed its methodology on collection data, and almost certainly is a record.

Overall, downtown has added 78,000 jobs, up 16.3 percent, since the recession-era trough in 2010.

The downtown gains were strong enough, combined with lesser growth in the rest of Chicago proper, that the number of total jobs reported by employers in the city hit 1.126 million, the highest since the 1.142 million level set in 2001, just before the city and national economy crashed. The overall city jobs total was up 1.7 percent compared with the prior year.

In comparison, the total number of unemployment-insurance-covered, private-sector jobs in the six-county metro area grew 1.5 percent, to 3.433 million. Cook (including Chicago) and Will counties saw employment grow 2.1 percent, but other suburban counties notably lagged: DuPage was up just 0.4 percent, and Lake County employers actually reduced jobs by 115, according to IDES.

Recent national employment growth has been about 2 percent a year.

Related: U.S. adds most jobs in 10 months

The new figures are likely to fuel what has been a lively debate—started during last winter's mayoral campaign and continuing on and off since—over whether downtown now is strong enough to stand on its own and whether the city should shift resources to other areas and tap downtown with higher taxes.

Mayor Rahm Emanuel has trumpeted the flow of big corporate headquarters to the Loop—some like Kraft Heinz, Gogo and Motorola Solutions coming from the suburbs, but others such as Oscar Mayer and ConAgra from out of state.

At the same time, though, the mayor has declared that downtown will receive no additional tax-increment financing projects—even for needed infrastructure—and this fall he pushed a record $588 million property tax hike that mainly would come from the central area and adjoining neighborhoods.

There also are questions about how long the back-to-downtown trend will continue, though such things are occurring to one degree or another throughout the country.

Another political implication: While Gov. Bruce Rauner can say that Illinois needs pro-business tax reforms, Emanuel can say that his part of the state is doing pretty well without them.

Finally, a couple of cautions on the data. They don't include self-employment or public-sector jobs. The latest data are preliminary and subject to minor revision. And IDES emphasizes that the figures reflect moves, shifts and reporting changes by employers, and thus were “not designed as a time series.”

Nonetheless, this is a good, solid set of numbers that have been collected the same way for many years. And the trend is very clear. With gains like this, the boom in downtown residential and office construction is likely to continue.