(NewsNation) — While the incarceration of U.S. WNBA star Brittney Griner in Russia was global news, the wrongful detention of Americans has become more widespread and harder to resolve over the past decade, according to a new study by the James W. Foley Legacy Foundation.

The study from the group, which advocates to free hostages and the wrongfully detained, found a 60% increase in the average length of a U.S. national’s captivity when taken hostage over the past 11 years. Several cases involved Americans being detained for more than 2,000 days spanning three presidential administrations.

“It is important to evaluate whether the structures currently in place are helping or hindering the recovery of Americans held hostage abroad,” the report stated.

On Thursday, Griner was returned to the U.S. in one of two recent prison swaps. In April, Russia released former U.S. Marine Trevor Reed after more than two years of detainment overseas.

Another former U.S. Marine, Paul Whelan, continues to be detained in Russia, where he has been held for nearly four years on suspicion of spying. Whelan’s family maintains he was attending a wedding in Moscow when he was detained.

Although the number of U.S. nationals taken hostage has decreased over the past decade, the cases appear to be increasingly difficult to resolve, according to the study. As a result, the total number of Americans held hostage each year has increased.

“Extensive bureaucratic processes, a lack of prioritization, and prolonged decision-making hinder the U.S. government’s ability to bring American hostages home in a timely manner,” the report stated.

Iran, China, Venezuela, Syria and Russia account for 75% of wrongful detentions of Americans, according to the study. The growing number of countries wrongfully detaining Americans has led to rising concerns that U.S. nationals are being increasingly targeted to secure political leverage against the U.S., according to the study.

From a recovery standpoint, however, a “wrongful detention” status can be hard to secure.

U.S. hostage recovery laws note the secretary of state is responsible for classifying someone as a wrongful detainee. According to the study, however, there are concerns about whether some requests ever reach the secretary of state.

Along those lines, U.S. hostage recovery laws don’t require that cases are referred in a timely manner to the special presidential envoy for hostages affairs.

Among the study’s recommendations was a requirement that the State Department reply to requests seeking wrongful detention status.

The study also advocated for better funding to benefit detainees’ families.

“The primary reason a wrongful detainee is being held is because they are Americans, and their captivities are used to leverage the U.S. government,” the report stated. “As a result, the U.S. government should be able to provide financial support to the families of wrongful detainees during a detention or for the detainees themselves after their return.”