The drop in the summer number followed a similar decline in the spring census for Center City - 261 vs. 429.
Last summer's homeless number was the highest in 10 years, putting pressure on city officials.
In May, Mayor Nutter announced a multipronged plan that included adding 700 units of housing for homeless individuals and families.
Sue Dichter, director of programs for the Bethesda Project, a provider of housing and services to homeless individuals, said it was difficult to get a complete picture of the city's street population. "It's hard to find everyone," she said.
She added, however, that the decision by Nutter to keep open through the summer two overnight "cafes" - stopgap shelters offering only minimum services - had "made a dent" in the street population.
Bethesda and another provider, Horizon House, run overnight cafes.
"We weren't open last summer," Dichter said. On the night of the census, the cafes were running at above capacity with 139 people.
Dichter said Nutter also opened up 45 new spots in recovery facilities last May, which also helped to move people off streets.
On any given night, more than 3,000 individuals and families sleep in city shelters, with several hundred more encamping on sidewalks, benches or parks. The quarterly street count gives the city, as well as service providers, a spot check on the situation.
Project HOME, a nonprofit that provides services and shelter to homeless people, has been conducting the census for about a decade. It divides the city into 11 zones and sends pairs of people to count people in each zone.
The U.S. Department of Housing and Urban Development now requires all cities to make once-a-year spot checks of street populations. Philadelphia's numbers are among the lowest for major cities.
According to recently released HUD data, Houston has more than 5,000 unsheltered homeless people, while San Francisco, Seattle and Atlanta each have more than 2,000 people on their streets.
Contact staff writer Jennifer Lin at 215-854-5659 or firstname.lastname@example.org.