The city known as America’s story factory is making up Census data.

In the latest allegation of The Post’s exclusive probe into fishy goings-on at the Census Bureau, a new whistleblower says workers in the Los Angeles region have been manipulating economic data.

Contact information for the veteran Census worker — who reached out to me by e-mail recently and whom I interviewed by phone — has been turned over to congressional investigators who are looking into data falsification in other parts of the country.

“Everybody knows falsification is going on,” the whistleblower told me, adding the malfeasance in the LA region is so obvious that it’s hard to miss.

She said she’s coming forward now because she “applauds” the others who have spoken up already.

Census employees have blown the whistle on the Denver and Philadelphia regions. A Denver whistleblower recently turned over information to the House Committee on Oversight and Government Reform.

A whistleblower in the Philadelphia region told me a year ago about the case of Julius Buckmon, a field rep who was accused of falsifying more than a hundred surveys each month. He was eventually caught and allowed to leave the bureau. But there was no public investigation until The Post broke Buckmon’s story last year.

Since then, the Inspector General of the Commerce Department, which oversees Census, and the House Oversight Committee, along with the Joint Economic Committee of Congress, have conducted probes.

Commerce Inspector General Todd Zinser found wrongdoing on the part of Buckmon — but exonerated the supervisors that Buckmon alleged ordered him to falsify data. Zinser also said he found no proof that the falsification was widespread.

The LA whistleblower means that 1 Census workers in four of the six regions (Chicago, LA, Denver and Philadelphia) have alleged data falsification. So far, I haven’t heard from anyone in the New York or Atlanta regions.

In what shouldn’t be a surprise to anyone, it appears that since The Post investigation, all of the regions are reporting more trouble getting people to respond to their surveys. That could be because Americans have suddenly gotten more shy about personal details. Or it could reflect less cheating because of heightened scrutiny.

Zinser said in his report there was no truth to allegations — made by a source to The Post last year — that the Census office in Philadelphia manipulated the national unemployment rate in the months before the last presidential election. In fact, Zinser said it was impossible to do.

But he either ignored or didn’t know that 120 computers — 11 of which belonged to supervisors — went missing from the Philadelphia Census office in September 2012, two months before the election. That information was disclosed only after The Post obtained the e-mails of Philly supervisors under a Freedom of Information Act request. Meanwhile, Commerce is fighting the release of many other e-mails.

The Oversight Committee also found wrongdoing with respect to Buckmon. It concluded that the Census’ data-gathering process had “vulnerabilities” that needed addressing.

But the committee also said it couldn’t measure the scope of the falsification problem because Commerce had “obstructed” its investigation.

The LA whistleblower says no one in official Washington has yet to reach out to her. But the allegation she is making can be easily checked by investigators without her help.

“There are some FSAs [field service areas] that month after month had a 100 percent response rate” to their surveys,” she said. “That alone should raise flags!”

“I can understand an occasional 100 percent response rate but you have to raise an eyebrow when some FSAs have 100 percent every month,” she said.

Although the numbers vary according to area and which survey is being conducted, each FSA consists of 10 to 15 field reps reporting to one supervisor. The reps scour the area doing interviews and report back to the supervisor.

If what the LA whistleblower says is true, either a bunch of field reps are awfully persuasive in completing interviews or they are filling in the survey answers themselves.

The other possibility: Supervisors are fudging the results on the reps’ computers to indicate interviews were successfully completed.

The stakes are high, of course. The Bureau of Labor Statistics requires a 90 percent success rate for interviews that go into the Current Population Survey, which Census conducts on BLS’ behalf. It’s those results that are used to calculate the nation’s monthly unemployment rate.

“To be perfectly honest, the BLS should be questioning the data, not just you alone,” the LA whistleblower said.