Actually, the "stereotypical kidnapping" abductions, where a child is taken by a stranger and kept over 24 hours have gone down for 115 in 1998 (when records were first kept) to 93 in 2001. These cases simply get more attention.

Most child abductions are by family members, and most of those are parental abductions. With the divorce rate tripling since 1960, there are bound to be more of these types of abductions.

"When the categories get conflated, the statistics can become confusing. Take the number 800,000: It's true that 797,500 people under 18 were reported missing in a one-year period, according to a 2002 study. But of those cases, 203,900 were family abductions, 58,200 were nonfamily abductions, and only 115 were "stereotypical kidnappings," defined in one study as "a nonfamily abduction perpetrated by a slight acquaintance or stranger in which a child is detained overnight, transported at least 50 miles, held for ransom or abducted with the intent to keep the child permanently, or killed." Even these categories can be misleading: Overstaying a visit with a noncustodial parent, for example, could qualify as a family abduction. Some individuals get entered into the database multiple times after disappearing on different occasions, resulting in potentially misleading numbers.

Many missing persons aren't reported at all—a 1997 study estimated that only 5 percent of nonfamily abductions (in which a nonfamily member detains a child using force for more than an hour) get reported to police. Some police departments may not even bother filing a report when a kid runs away from home for a few days. It's also easy to lose track of abduction cases, since some of them get filed away under associated crimes, like homicide or sexual assault."

http://www.slate.com/id/2157738/