MITCHELL, S.D. (AP) - South Dakota is bucking the trend of declining numbers of baby boomers, while North Dakota is not.

Although the baby boomer population is declining nationally, numbers are up in 18 states including South Dakota.

Mark Mather, associate vice president of domestic programs for the Population Reference Bureau, said the national decline is due to the aging process. The oldest boomers are 62, and some are dying.

South Dakota's baby boomer population grew just 1 percent from 2000 to 2007, but it was the 12th fastest growth rate in the nation and stood in contrast to the national decline of 1.4 percent.