New York City's Hispanic population changed markedly over the last decade as the once dominant Puerto Ricans lost their plurality and the number of people of Mexican ancestry tripled.

That shift, and other contours in the city's ethnic landscape, emerged from 2000 census data that was released yesterday and provided new details about the state's increasingly diverse Hispanic and Asian minorities.

Over all, the figures showed that the city's traditional ethnic heavyweights — among Hispanics, the Puerto Ricans, and among Asians, the Chinese — faced competition for the first time in the 1990's from other fast-growing groups.

The number of Puerto Ricans in the city slipped by 12 percent over the decade, a drop that demographers and community groups attribute to the accelerated movement of retirees back to the island and successful families to the suburbs.

At the same time, a surge of new immigrants from Latin America and the Dominican Republic magnified the effects of that population decline, reducing Puerto Ricans to a mere 36 percent share of the city's Latino population. In 1990, they represented slightly more than half of all Hispanics in the city.

Their reduced numbers, however, are unlikely to trim back Puerto Rican political dominance.

"I don't think it changes the immediate makeup of the Latino leadership here, where Puerto Rican officials and policy makers are still the main voice speaking for all Latinos," said Juan Figueroa, president of the Puerto Rican Legal Defense and Education Fund.

Instead, he said, more diversity in the Hispanic population should ultimately produce a broader coalition of Latinos speaking on shared issues. "It's not a zero-sum game," Mr. Figueroa added.

Meanwhile, people of Mexican descent, nearly invisible in the panoply of Latino groups just 10 years ago, have become the third biggest single group of Hispanic New Yorkers, after Puerto Ricans and those of Dominican ancestry.

Staten Island and Queens showed the biggest growth in people of Mexican background in the city, although comparable increases occurred over the decade in the suburban counties radiating out from New York, like Orange, Westchester and Dutchess.

"New York became a destination over the past decade in part because Mexico had an economic crisis in 1994 and 1995," said Salvador Beltrán del Río, the Mexican consul general in New York. "At the time you also had a very strong anti-immigrant movement in California, so people didn't want to go there or they wanted to move from the West Coast to the East. Plus, compared with other states, the economy of New York and the Northeast in general has been strong, so there has been a lot of work."

Colorful evidence of how that migration has become rooted in New York soil could be seen last Sunday in the shadow of Yankee Stadium, where the Diaz Mexican Soccer League opened its season with a day of music, fast food and ceremony at Macombs Dam Park.

As the No. 4 subway train rattled by above their heads and the mariachi band hired for the occasion took a break, hundreds of weekend sportsmen from Mexico paraded around the park in uniforms plastered with the names of beer distributors, soft drink companies, Mexican restaurants and groceries.

There were the Guadalajara Club, Atlas Tecuauti and Real San Sebastian, some with flags proclaiming their name and others accompanied by someone's girlfriend or sister or wife dressed in a long gown or miniskirt. The Diaz league, named for the Mexican-American businessman who owns it, is only one of at least six such leagues in the city and New Jersey.

Most of the soccer players are relatively new arrivals.

"When I first came, it was very hard because there weren't many Hispanic people near me," said one player, Martin Morales, a 28-year- old Manhattan restaurant worker who left his home in Mexico City for Manhattan in 1992.

"But the next year, I looked around my neighborhood and in the yards I saw a few more Latinos," he recalled. "The year after that, there were a few more. And now, everyone in all the yards around me is Latino. It's very comfortable."

Daniel Cisneros, another Mexico City native, came to New York eight years ago, at 17, with every intention of eventually returning home. But, in a typical immigrant pattern, life here began to bind him with responsibilities and relationships.

He started to make money working at a dry cleaner in Long Island City, Queens. He met a young woman, also an immigrant, from the Mexican state of Puebla. They married, and now Mr. Cisneros has a 6- year-old son, Christian, who is an American citizen because he was born in New York.

Asked the name of his weekend soccer team, Mr. Cisneros responded, "Las Águilas." Christian, on the other hand, answered the question in English: "The Eagles."

Now, said Mr. Cisneros, it does not seem logical to go back to Mexico. "Our country is poor," he said. "We have to be here to help those who are left there."

City planners say that the Mexican growth spurt largely reflects the recent migration of Mexicans to New York from other parts of the United States, and that these newcomers in turn will attract more family members from home.

"Once you have a community here and a welcoming environment that includes social and employment connections, more people follow," said Joseph B. Rose, chairman of the City Planning Commission. "What starts off as a trickle becomes a steady flow as long as it's a place where people want to come."

About half the reported growth in the population of the city as a whole and for individual ethnic groups is a result of better counting in the 2000 census, Mr. Rose added.

No one has accurate figures, but consular officials said that many of the area's Mexicans are probably living illegally in the country. While immigrants used to shuttle back and forth with relative impunity, they now face harsh penalties if caught at the border. The new laws, passed in 1996, appear to have encouraged more people to settle in the United States.

The latest census figures provided some information about Hispanics who identified themselves as Puerto Ricans, Mexicans or Cubans. All the rest — including those of Dominican, Colombian or other Latin heritage — were lumped together as "other Hispanics."

In New York City, long a magnet for immigrants from the Caribbean and now from South and Central America, that "other Hispanics" category encompasses more people than the other three combined, or more than 1.1 million people. Nationwide, by comparison, the "other" Hispanics accounted for less than one-third of the 35.3 million Hispanics counted in the 2000 census.

The trend toward more diversity in national origins was also evident among Asians, although less sharply so, according to the new census data.

The number of people of Chinese descent grew over the decade, but by barely 51 percent compared with growth of more than 90 percent between 1980 and 1990. The proportion of Asian New Yorkers who identified themselves as Chinese also slipped slightly.

At the same time, in a dynamic similar to that of Hispanics, other Asian groups appeared to grow at a faster rate than Chinese. The population of people of Indian descent, for example, increased by about 81 percent in both the city and across the state over the last decade.

And the number of Asians who did not fit into one of the categories listed on the census form — that is, people who did not identify themselves as Indian, Chinese, Filipino, Japanese, Korean or Vietnamese — also doubled in the city. Among those are Bangladeshis and Pakistanis, two of the city's fastest-growing immigrant groups.