More than 40 percent of the state's 5.6 million residents are Hispanic, black or Asian, making Maryland one of the most diverse states, according to new U.S. Census estimates.

Maryland is one of nine states in which minorities account for at least four of every 10 people, based on 2004 population estimates. In 1990, minorities made up 30 percent of the state's population.

William Frey, a demographer at the Brookings Institution in Washington, said minorities who have traditionally been drawn to urban centers such as Washington and Baltimore are now living in the suburbs, particularly after they have children. Jobs, more affordable housing and higher-performing school systems are attracting minority families, just as they attracted the non-minorities who came before them.

"It's part of suburbanization," he said.

The biggest growth has been in the number of Hispanics. Between July 2000 and July 2004, Maryland gained more than 67,000 Hispanics, for a total of 298,000, or 5.4 percent of the population. By comparison, the state gained 104,000 Hispanics throughout the 1990s, according to census data that Frey analyzed.

The Asian population increased by about 39,000, for a total of 286,000, or 5.1 percent of the population, from July 2000 to July 2004. The number of blacks jumped by 109,000, to 1.66 million, or 33.4 percent of the population, during the same period.

The number of non-Hispanic whites increased as well, but at a much slower pace. The state gained about 20,000 whites in the past four years, to reach 3.35 million, after losing 31,455 during the 1990s.

The minority newcomers have caused schools to add bilingual staff members and English for Speakers of Other Languages classes. They have also added top students, researchers and workers to the state's universities and technology companies. The increase in population has fueled economic growth, with more minority-owned businesses, as well as brought problems of poverty.

But some experts believe that significant political change is a few years away.

"The numbers reflect raw population, not likely voters," said Keith Haller, president of Potomac Inc., a Bethesda-based polling company. "We're still at least one election cycle away from when Asian and Hispanic populations will decide electoral outcomes in proportion to population and actual votes at the ballot box."

Hispanics represent about 2 percent of the state's registered voters, Haller said. That community is splintered, with organizations that are not aligned politically. By contrast, the African American community has been relatively unified for years, making it a driving force in Maryland Democratic politics.

Much of the change has been at the local level, where Hispanics have been elected to the legislature and county councils.

As Maryland grows more diverse, "it certainly will allow minority leaders to demand more from government and politicians," Haller said. "I think the time is right for the maturing and growth of these minority constituencies."

Among the other states where minorities make up at least 40 percent of the population are New York, Arizona, Georgia and Mississippi. California, New Mexico, Texas and Hawaii are "minority-majority" states, with non-Hispanic whites making up less than 50 percent of the population.