Ken Jennings did some research on this for his book, Because I Said So!: The Truth Behind the Myths, Tales, and Warnings Every Generation Passes Down to Its Kids. The figure above about 25 deaths per year is correct, but it does omit the fact that almost all of the deaths involved dry cleaning or trash bags where the child crawled in.
Today, the U.S. Consumer Product Safety Commission reports that plastic bags still kill about twenty-five American kids per year, almost 90 percent of whom are infants. The typical encounter a larger trash bag or dry-cleaning bag, which an infant crawls or falls into, or pulls over their face .... please note that garden-variety shopping bags, the kind you're most likely to have around, are generally blameless, and older kids are safe around bags no matter what.
Admittedly, he doesn't provide sources or statistics for how he got the "typical encounter", but in other parts of the book, such as "poisoned Halloween candy" or "running with scissors", he breaks down his examples by showing that he did diligent research and looked at the individual cases, so I'm apt to believe that the details here were covered as well.
It's probably worth noting that a substantial amount of his book is dedicated to the idea that many of these behaviors are indeed potentially hazardous, but that the risk has been so exaggerated that people are spending needless time worrying about something that isn't likely to happen when they could be spending that time protecting against plausible dangers.