If you come across the data please share it, it would be worthwhile seeing what exactly they're talking about and if the data matches your memory of it. I didn't come across it in my (very limited) search, but I did find this analysis that suggests U.S. citizens fare worse than citizens of many other countries[1]:

> According to a database compiled by New America from public sources, since 2001, American hostages taken captive by terrorist, militant, and pirate groups have been more than twice as likely to remain in captivity, die in captivity, or be murdered by their captors as the average Western hostage. Forty-three percent of American hostages died, remain in captivity, or remain unaccounted for, compared to an average of 19 percent for all Westerners.

[1] https://www.newamerica.org/international-security/policy-pap...