New York (CNN) -- City officials will formally challenge the Census Bureau's data for New York City, which Mayor Michael Bloomberg said understated the number of residents in Brooklyn and Queens and overstated the number of vacant housing units in the city.
Although New York was named the most populous city in the country with 8,175,133 residents, its meager 2.1% increase since 2000's census count left many elected officials skeptical that every New Yorker was accounted for.
The Census Bureau reported that Brooklyn's population increased by just 1.6% and Queens grew by just 0.1%, gaining only 1,300 people since 2000.
"That can't be possible," Bloomberg said at a news conference in Queens Sunday, where he announced his intent to dispute the results.
As evidence of this so-called undercount, Bloomberg cited census reports of an increase in vacant housing units and a decrease in population in neighborhoods such as Astoria and Jackson Heights, Queens -- both known for their diverse immigrant communities.
"Everything we know about these neighborhoods tells a different story," he said. "They are vibrant, vital communities. People who have tried to find apartments in these neighborhoods can confirm there just isn't an abundance of vacancies."
Bloomberg suggested that empty housing numbers were "implausibly high" because Census Bureau workers marked homes as vacant if they were unable to contact residents.
Getting an accurate count in densely populated areas is tough for the Census Bureau, and New York especially so. In Queens, more than 140 languages are spoken in the public school system.
But the stakes are high. If the city is successful in its challenge of the census numbers, it could affect the amount of federal aid the city receives.
Census projections of New York City's population released last year estimated that the city was home to about 8.4 million people -- which Bloomberg pointed out amounts to a 225,000-person discrepancy with the current numbers.
The mayor wasn't the only elected official to complain. Sen. Chuck Schumer, a Democrat and resident of Brooklyn, also got in on the act.
"The Census Bureau has never known how to count urban populations and needs to go back to the drawing board," he said in a statement. "It strains credulity to believe that New York City has grown by only 167,000 people over the last decade. To claim that growth over the last decade in Brooklyn was 1.6% and growth in Queens was .1% flies in the face of reality."