Some good news from the Centers for Disease Control and Prevention as swimsuit season approaches: People don’t seem to be drowning as often as they used to.

Unintentional drowning deaths in the United States decreased 9 percent between 1999 and 2010, according to figures released Tuesday morning, with the sharpest decline among infants under 1. Deaths also reduced among older children and young adults. But deaths increased nearly 10 percent for one group – people ages 45 to 84.

The report’s author, Jiaquan Xu of the National Center for Health Statistics, did not offer any reasons for the changes. But others who have noticed the positive trend point out that it could be the result of public health efforts aimed at promoting bath and pool safety for young children, for whom accidental drowning had become a major cause of death in the United States.

(This link contains some upsetting photos and stories of children being sucked into these powerful drains at their local pool) Federal legislation enacted in 2007 requires pools and hot tubs to have covers over their drains, which can entrap children.

State and federal health authorities have tried to emphasize to parents that children under 6 are not to be left unattended in the bath. And virtually every American parent has heard the warning that babies can drown in as little as one inch of water.

But there were no immediate reports I could find that might explain why drowning deaths among older adults are rising. Have any ideas or information? Please list them in the comments.

Some other factoids from today’s report:

- A total of 46,419 Americans died from accidental drowning between 1999 and 2010

- People are more likely to die from drowning on the weekend than on the weekdays (No reason for this one but I suppose it’s obvious)

- For males, drowning was most likely to occur in natural water like a lake or river, accounting for more than half of drownings over that time period. Females were equally likely to have died in natural water, bath tubs and swimming pools.

- Since 2005, drowning has surpassed car accidents as the leading cause of accidental death among boys age 1 to 4.