The 2010 census tally isn't over yet and Philadelphia's population is already growing - at least on paper.

According to the Census Bureau's first 2009 estimate, the city's population stood at 1,547,297 as of July 2009. The data, released this week, puts the city about 7,000 residents ahead of its 2008 population.

It also means that Philadelphia has added nearly 30,000 residents since the 2000 census, which would be the city's first population gain since 1950.

"Estimates are great, but what really matters is the head count we're undergoing today," said Tricia Enright, director of Philly Counts, the city's census-education campaign. "Let's fill out those forms and show everyone that the city of Philadelphia is on the move."

The city's population peaked at more than 2 million in 1950 and had steadily declined ever since.

The new estimate takes into account the number of births in the city minus the number of deaths between July 1, 2008, and July 1, 2009. It also factors in international and domestic migration, said Greg Harper, a demographer with the Census Bureau.

The bureau routinely releases yearly population estimates between official counting years, Harper said. After the 2010 count is complete, the bureau will compare its estimate to the actual figure.

After the 2000 census, the bureau found that, overall, its estimates were 2.3 percent lower than the actual count. In Philadelphia, the bureau was off by about 100,000 people: It had estimated that the city had 1,419,000 people and the count came in at 1,517,000.

In 2008, the bureau originally put Philadelphia's population estimate at 1,447,395. The city challenged the figure.

The number was changed after the bureau did a more accurate tally of people living in prisons, nursing homes and college dorms. The change meant that the city was eligible for more federal funding.