Birth rates are falling dramatically for black and Hispanic teenagers, but they continue to be much higher than the birth rate for white teens.

The Hispanic teen birth rate fell by half over about eight years, and the black teen birth rate dropped nearly that much. But even with those declines, the white teen birth rate is still only half as high, the Centers for Disease Control and Prevention reported Thursday.

"Despite this historic progress, profound disparities remain," said Bill Albert, chief program officer for the National Campaign to Prevent Teen and Unplanned Pregnancy.

The teen birth rate has been falling since 1991, which experts attribute to more teens using birth control and more waiting until they are older to have sex. But in the new report, the CDC focused on 2006 through 2014 - the most recent phase of the decline, when the fall was steepest.

The agency saw declines in every state and in every racial and ethnic group.

The recent drops in the black and Hispanic teen birth rates look more dramatic in part because they started at far higher rate, Albert said. The Hispanic rate fell 51 percent - from 77 to 38 births per 1,000 Hispanic girls ages 15 to 19. The black rate fell 44 percent - from 62 to 35 per 1,000.

The white rate fell 35 percent, from 27 to 17 per 1,000.

Teen births have been declining across the country, through the drop has been greater in some states than others. The teen birth rate fell nearly 50 percent in Arizona, Colorado and Connecticut, but only about 13 percent in North Dakota and 15 percent in West Virginia.

Arkansas, Mississippi and New Mexico have the highest teen birth rates; each state sees more than 40 births to teen moms per every 1,000 girls ages 15 to 19.

Massachusetts and New Hampshire have the lowest, at 11 per 1,000.

About 4 million babies were born in the United States in 2014. Of those, about 250,000 were born to mothers ages 15 to 19.