Throughout the pandemic, anecdotes about households departing cities for the suburbs were everywhere. New data from the Census Bureau lends credence to that narrative, with Philadelphia suffering a steep population decline.

From July 2020 to July 2021, the number of people moving away from the city of Philadelphia outnumbered those moving to the city by more than 28,000, according to the Census Bureau's annual population estimate released on Thursday and reported by the Philadelphia Inquirer. When birth and death numbers are included, they show Philly losing an estimated 24,754 people, or 1.5% of its 2020 population, which would be the largest one-year drop for the city since 1975.

Despite the thousands of Philly residents decamping for nonurban areas with more outdoor space, suburban Philadelphia counties saw comparatively modest population growth during the year in question, according to census data. Overall, the Philadelphia metropolitan area lost a net of 14,000 people, a far cry from the New York metro's loss of 385,000 over the same time period.

Though some of New York's loss was the Philly region's gain, it wasn't enough to overcome the dominant population trend of those 12 pandemic months: households fleeing high-cost metropolitan areas either to farther-flung towns or other metropolitan areas with less density and lower housing costs, according to the Census Bureau's announcement of the data's release.

The fact that the Philly region's multifamily market has performed so well since early 2021 is even more striking against the backdrop of a shrinking population, and underscores the degree to which a lack of supply is driving up rent and home purchase prices.

Aside from people movement, Philadelphia's birth rate was at its lowest in at least 20 years, with its death rate the highest it has been since at least 2001, the Inquirer reports. The city still had slightly more births than deaths, unlike 73% of U.S. counties, according to census data.

Perhaps the largest drag on Philly's population growth in the past five years has not been death, but a drop-off in international immigration due to policies put in place by the administration of President Donald Trump, the Inquirer reports. Immigration has historically been among the most reliable drivers of population growth in U.S. cities, and a loosening of immigration policy under President Joe Biden could correspond with a recovery in in-migration numbers.

The 12 observed months were the first such period in census data to take place entirely during the pandemic, but the annual estimate is considerably less reliable than the decennial census conducted most recently in 2020. After annual estimates showed steady but modest population growth in Philadelphia from 2011 to 2019, the 2020 census resulted in a spike of 16,000 people, partly due to what researchers see as consistent underestimation, the Inquirer reports.