In about 15 years, Latinos will replace whites as the majority population segment in a six-county North Bay region, but the shift will come later in Sonoma and Marin counties where the cost of living is expected to remain among the highest in the state.

Also, the growth of predominantly younger Latinos will replace aging baby boomers, leading to a reversal of the ?graying? population trend by 2022.

The demographic projections were contained in a study released Thursday by Dr. Robert Eyler, chairman of the Sonoma State University Economic Department.

His study, commissioned by the North Bay Leadership Council, covers Lake, Marin, Mendocino, Solano, Sonoma and Napa counties. Eyler analyzed Department of Finance and Census 2000 figures for ethnicity and age.

He said the Latino population is expected to grow faster than any other group because of immigration and a higher birth rate.

Solano County will be the first to experience the change, expected in about 2023. Marin and Sonoma counties will not be predominantly Latino before 2050, he said.