Numbers produce an image of a city's place in time. For Philadelphia in 2012, the picture is of a city in transition on a number of fronts. There are familiar problems and one promising demographic trend.

In the last year, unemployment in the city was down, but job creation slowed from the year before. Residential building permits were up, but home sales dropped a sixth straight time. Violent crime fell overall, while the homicide total increased for the second year in a row.

One positive sign for the city's future, as reported in a new statistical analysis by Pew's Philadelphia Research Initiative, is that the number of young adults in Philadelphia has risen substantially in recent years. The question is whether those young people will find the place attractive enough to stay.

Some of the city's long-term, underlying problems have returned to center stage in this postrecession era. Among them are crime, poverty, an educational system facing serious difficulties, and a city government strapped with rising pension and health-care costs. In this year's Pew poll, more residents say the city has gotten worse in the last five years than say it has gotten better.

Philadelphia's economic recovery has not been particularly strong, although the number of jobs in the city did grow in 2011 by 2,100. Overall employment in the city is still below what it was in 2008, before the global financial crisis. That is also true for the nation as a whole.

Unemployment among residents fell 1 percentage point to 10.5 percent at year's end, mirroring a drop in the state jobless rate. The decline was slightly less than the drop in unemployment nationally. At the same time, the percentage of individuals over age 16 not in the labor force, 42.1 percent, is one of the highest of any major city, a long-term drag on economic growth.

Residential construction permits grew in 2011, reaching a level not seen since 2008 and indicating that there has been some improvement in the hard-hit construction sector. However, sales of existing residential property declined yet again, down 59 percent from the recent peak achieved in 2005.

Crime is much on the minds of Philadelphians these days; our poll found that 75 percent of them view it as a "serious" or "very serious" problem in their neighborhoods, up from 64 percent a year ago. It is not hard to see why - the number of murders in the city rose in 2011 from 306 to 324. While violent crime as a whole was down 2 percent, major crime, which includes burglary and theft, was up a little more than 1 percent. All of these numbers had been dropping between 2006 and 2009.

The systems that provide K-12 education in the city face a time of continued uncertainty. The School District of Philadelphia is grappling with huge budget problems and a dwindling enrollment, now down to 146,090, as it seeks to close some schools and take other steps to downsize its operations. Also faced with fewer students, the Archdiocese of Philadelphia is shuttering 11 of its 65 schools in the city, after initially proposing to close many more.

Enrollment in taxpayer-supported charter schools continues to rise. As recently as five years ago, there were more students in the city's Catholic schools than in the charters. Today, Catholic-school enrollment is less than half of the charters' total.

And there is poverty, which has plagued the city for decades. Perhaps not surprisingly, given the severity of the recent economic downturn, the share of Philadelphians classified as poor grew from 25 percent to 26.7 percent in the latest U.S. Census Bureau figures, again making Philadelphia one of the poorest big cities in the country.

The local poverty rate is 31 percent for families with children and 47 percent for families headed by a woman. It is 31 percent for African Americans and 41 percent for Hispanics.

For city government, a big problem is the cost of city workers' benefits, including pensions and health care. Those costs, which were 20 percent of the city budget a decade ago, account for 32 percent now, leaving less money for other priorities.

The best news for Philadelphia may be on the demographic front. According to the census, this increasingly diverse city has been doing quite well in attracting residents between the ages of 20 and 34. In the 2010 census, it had 392,779 of these young adults, up from 342,473 a decade earlier. This growth came at a time when the age group's share of the national population was declining. For Philadelphia, a key challenge moving forward is to hang on to those people as they get older and their incomes and/or families grow.

Meeting that challenge will not be easy. But Philadelphians are confident about the city's future. In our latest poll, they said that they expect the city to be better in five years than it is now. The ratio was nearly 3-1. For people who have lived in the city 10 years or less, it was more than 4-1.

That optimism comes as no surprise. Four years of polling, all of it during tough times, have taught us that the resilience of Philadelphians runs deep.

Larry Eichel is project director of the Philadelphia Research Initiative of the Pew Charitable Trusts. The report "Philadelphia: The State of the City, a 2012 Update" is available at