In Philadelphia, the number of immigrants keeps growing.

The foreign-born population increased 69 percent from 2000 to 2016  — to more than 232,000 — and now represents nearly 15 percent of all city residents, according to a new analysis by the Pew Charitable Trusts.

That's the highest share since World War II.

The newcomers have helped drive Philadelphia's recent population growth following a half-century of decline, increased its workforce, and boosted the number of entrepreneurs. At the same time, the study said, immigrants have added to the already large pool of poor and less-educated residents, and increased the number of people who struggle to speak English, putting demands on schools and services.

They make up 19 percent of workers and 14 percent of those in poverty.

The study, "Philadelphia's Immigrants: Who They Are and How They Are Changing the City," was released Thursday afternoon. It relied mainly on census data to examine the changing characteristics of the city's foreign-born population without regard to their immigration status.

"The degree to which immigrants have fueled Philadelphia's population resurgence is striking," study author Tom Ginsberg, a manager with Pew's Philadelphia research initiative, said in a statement. "Pew's research shows the potential they have to shape the city's economic and social landscape in ways that present both opportunities and challenges."

The immigrant population is diverse, with no single nationality close to having a majority. Recent census estimates show China was the leading nation of origin, accounting for about 11 percent of the city's immigrants. India, Vietnam, and the Dominican Republic each accounted for about 6 percent or 7 percent, while Mexico, Ukraine, Haiti, and Jamaica each had 3 percent or 4 percent.

Since 1990, Philadelphia has again become an attractive destination for immigrants. At peak in the 1850s, the foreign-born share of the city population was 30 percent, twice the current figure.

Other significant findings included:

— Between 2000 and 2016, as the city population increased from 1,517,550 to 1,567,872, the number of foreign-born residents rose by about 95,000. At the same time, the number of U.S.-born Philadelphians fell by 44,500.

— In 2016, nearly one in five working Philadelphians was an immigrant. Many held service jobs in health care, education, hospitality, and retail.

— The median household income of immigrants was about $39,700, close to that of U.S.-born Philadelphians. The poverty rate among immigrants was 24 percent, slightly below the rate for natives. But in recent years, the number of immigrants living in poverty has been growing at a faster rate than that of natives.

— Although about three in 10 adult immigrants had college degrees, slightly higher than the share of U.S.-born residents, another three in 10 had little schooling, a significantly higher share than the native population.