PHOENIX — A new report suggests an upcoming surge in Arizona’s Hispanic population.

Figures from the U.S. Census Bureau show that the percentage of Hispanics in most counties is increasing.

For example, in Maricopa County the figure is up to 31 percent from less than 25 percent at the beginning of the decade. Pima County saw the share of residents who said they are Hispanic go from 29.3 percent in 2000 to more than 33 percent now.

But some of the data suggests that rate of change could accelerate — and sharply.

In Maricopa County, nearly half of those younger than 5 are Hispanic, up from 40 percent in 2000. Pima County, at less than 47 percent at the beginning of the decade, already is up above 51 percent.

And Yuma County, where half of the residents already are Hispanic, the figure for its youngest residents is more than three quarters.

The report does not detail the components of the population change. But figures from the Arizona Department of Health Services provide what could be a critical clue: The birth rate of Hispanic women is twice that of Anglos who do not identify themselves as Hispanic.

In most counties, the growth rate of Hispanic population is sharply higher than the non-Hispanic population, often by multiples.

Maricopa County, for example, showed an increase of only about 18 percent since the beginning of the decade of those who did not identify themselves as Hispanic. By contrast, the number of Hispanics in the county jumped by more than 60 percent.

A nearly similar ratio exists in Pima County, where Hispanic population since 2000 is up by more than 35 percent, versus just 13.5 percent for non-Hispanics.

In Yuma County, the disparity was even larger: less than 9 percent population increase of non-Hispanics since 2000, versus almost 34 percent for Hispanics.

But Pinal County, which has experienced a population explosion since the decade began, recorded an approximately equal rate in the increase in numbers of both groups.