Kim Hjelmgaard

USA TODAY

Beheading, hanging, lethal injection, shooting — the number of people executed by countries in 2015 hit a 25-year high, according to new figures published Wednesday by Amnesty International, the British human rights group.

At least 1,634 civilians were executed by governments last year using various methods, an increase of 50% compared to the year before, Amnesty said. Although 89% of those killings took place in just three countries: Iran, Pakistan and Saudi Arabia.

The numbers exclude China, where these data remain a state secret, although Amnesty said thousands were almost certainly killed there in 2015 by the government.

Salil Shetty, Amnesty International’s secretary general, called the findings "profoundly disturbing."

"In 2015 governments continued relentlessly to deprive people of their lives on the false premise that the death penalty would make us safer," Shetty said.

In Pakistan, Amnesty said the increase in executions was driven by the lifting of a moratorium on civilian executions. The nation sent 320 people to the gallows in 2015.

Iran killed 977 people, mostly for drug-related offenses. It put to death four people who were under 18 at the time they committed their crimes.

Executions in Saudi Arabia jumped 76% to at least 158 people. Most of them were beheaded but firing squads were also used and in some instances the executed bodies were displayed in public, according to Amnesty.

The top five places where executions occurred last year — in order by volume — were China, Iran, Pakistan, Saudi Arabia and the United States.

Amnesty said the U.S. carried out 28 executions, the lowest number since 1991. The number of death sentences imposed in the U.S. hit a low last seen in 1977: 52.

Despite the rise in executions in 2015, Amnesty said that for the first time ever the majority of the world's countries — 102 — have now fully abolished the death penalty. Fiji, Madagascar, Republic of Congo and Suriname were among the countries that outlawed the practice last year. Mongolia will prohibit it from 2016.