NEW YORK — Amnesty International reports that there was a dramatic 54 percent increase in executions globally in 2015, with Iran, Pakistan and Saudi Arabia responsible for nearly 90 percent of the killings.

The human rights organization said that the figure of at least 1,634 people executed last year — up from 1,061 in 2014 — does not include executions in China where data on the death penalty is considered a state secret.

Amnesty International’s Secretary General Salil Shetty told several reporters Tuesday that for China “our estimate is that they execute as much as the rest of the world.”

He said China is currently reviewing crimes punishable by the death penalty so there is “a slim ray of hope” that the number of executions may be reduced.

On the upside, Shetty said, four countries abolished the death penalty for all crimes in 2015 — Republic of Congo, Fiji, Madagascar and Surinam — bringing the global total of countries now banning executions to 102.

Mongolia is set to abolish the death penalty this year, China and Vietnam reduced the number of offenses that can be punished by death, and Malaysia announced legislative reforms to review the country’s mandatory death penalty laws, Amnesty said.

In addition, Burkina Faso, Guinea, Kenya and South Korea considered legislation to abolish the death penalty, it said.

When Amnesty International began campaigning against the death penalty in 1977, only 16 countries had fully abolished the death penalty.

“The overall trend is very clear,” Shetty said, “more than half the world’s nations have abolished the death penalty.”

In the United States, 28 people were executed in 2015, nearly half in Texas.