A new study shows that in the third quarter of 2005, African Americans and Hispanics were the heaviest users of cell phones, and their rate of growth was faster than other ethnic groups.

The study, done by Telephia, shows that African American cell phone owners used an average of 1,200 minutes, and their use was growing at a rate of about 10 percent between the first and third quarters of 2005. Hispanic cell phone owners, meanwhile, used on average about 979 minutes, and their rate of growth was about 13 percent.

Consumers who fell under the mixed racial background category used 888 voice minutes, while Asian or Pacific Islander consumers used 845 minutes. Both White/Caucasian and Native American/Alaskan mobile phone consumers logged 632 and 623 total voice minutes, respectively, the least among all groups.

Quarter-by-quarter figures show use among all groups is growing.

"Overall growth in cell phone usage demonstrates a robust consumer demand for newer and better wireless products and services," said Tamara Gaffney, Telephia's product director, in a statement. "And the wireless industry is not the only sole beneficiary of the demand. Technological advances and better service offerings have reduced cost per minute charges for consumers over time."

The study also showed that users aged 18-24 use their cell phones the most, spending more than 1,300 total voice minutes on average per month. Youth mobile phone use is 71 percent more than the total average minutes used by all age groups.

Cell phone users aged 25-36 used on average 970 minutes; 37- to 55-year-old users used 726 minutes; consumers 56 and older used on average 441 minutes.