WEST POINT, NY — (CNN) Americans kidnapped by jihadist groups are killed at nearly four times the rate of other Western hostages in captivity, while American hostages are the least likely to be released, according to a report released Thursday.

The report, issued by West Point’s Combating Terrorism Center, found that six countries — the United States, Turkey, Italy, the United Kingdom, France and Germany — account for more than 60% of Westerners kidnapped by jihadist groups around the world since 2001.

The report attributed the higher rate of abduction of individuals from these countries less to their nationalities and more to the “increased target availability or an expansion by jihadists of their zones of operation.”

While being a “Westerner” may be central to the kidnapping of an individual, the study suggested that Americans were not a particular target at the abduction stage.

However, the report noted that some of the countries with higher release rates than the United States — and the U.K. — had occasionally paid ransoms or conducted prisoner exchanges.

“Nations who refuse to negotiate with jihadist organizations have a higher risk of their citizens being executed,” the report found.

The 68-page report analyzed over 1,400 cases around the globe, with jihadist kidnappings in the Middle East and Africa the central focus.

Of the approximately 36 global jihadist organizations, ISIS, the Taliban, and al Qaeda in the Islamic Maghreb — the al Qaeda franchise operating in northwestern Africa — account for 70% of the abductions of Westerners, according to the report.

However, the report noted that there were “multiple cases” where little-known militant or criminal groups did the initial abductions before giving or selling their captives to the jihadist group eventually deemed responsible for the kidnapping.

ISIS was found to have the highest execution rate of its western hostages amongst jihadist groups, while there was no record of Jabhat al-Nusra, the al Qaeda affiliate in Syria, or Boko Haram, a terrorist group based in Nigeria, ever having executed a Western hostage.

Altogether, jihadist groups released just over 60% of their hostages. And while jihadist groups tend to hold more hostages than other non-state entities, such as Somali pirate groups, they don’t keep them for as long. The report found that 18% of the latter abductions exceed six months, while more than 60% of abductions by jihadist groups are resolved between two weeks and six months.

Journalists and NGO workers had the highest rates of abduction, according to the report.

The report was compiled following the beheadings of Americans James Foley and Steven Sotloff, both journalists, and aid worker Peter Kassig at the hands of ISIS, and the death of American Kayla Mueller, also an aid worker, in ISIS captivity.

But overall, Westerners who die in captivity are more likely to face death from causes other than execution, such as being killed during the course of a rescue attempt, the report said.

Luke Somers, an American photojournalist, was killed in Yemen last year during an attempted rescue mission by U.S. Navy SEALs and American Warren Weinstein and Italian Giovanni Lo Porto, both aid workers held captive by al Qaeda, were killed earlier this year when a U.S. drone strike struck an al Qaeda compound where the pair were unknowingly held.

The report noted that there appeared to be a reduction in jihadist kidnappings in 2015, possibly because of the publicity surrounding the gruesome beheadings by ISIS and the impact that might have had on individuals’ willingness to travel to high-risk areas.

Authors Seth Loertscher and Daniel Milton cautioned against reading too much into the trend, however, until more information becomes available in the months ahead.

The report examined multiple sources of information, including the Global Terrorism Database at the University of Maryland and data from private sector companies, but the authors said there is likely underreporting of kidnapping incidents because of a reticence to publicly discuss the specifics of ransoms or other sensitive factors.

The-CNN-Wire ™ & © 2015 Cable News Network, Inc., a Time Warner Company. All rights reserved. (PHOTO: ISIS)