At least 20,000 prisoners are awaiting execution worldwide and more than 2,000 were put to death last year, a leading human rights group has said.
The US and China carry out executions by lethal injection
In its annual survey on the death penalty, Amnesty International said 94% of the 2005 executions took place in China, Iran, Saudi Arabia and the US.
The numbers are down from 2004 thanks to a "global tide" against the death penalty, the group said.
But it said the number may be higher as many countries do not release figures.
There were 2,148 known executions in 22 countries in 2005, Amnesty International said, down from a record level of 3,797 in the previous year.
At least 1,770 executions took place last year in China, where a person could be sentenced and executed for non-violent crimes including tax fraud, embezzlement and drug offences, the UK-based group said.
It was a worry that that high profits behind the country's organ transplants from executed prisoners may act as an incentive to maintain the death penalty, the group added.
Last year, at least 94 people were executed in Iran, 86 in Saudi Arabia and 60 in the US. Overall, 5,186 people were sentenced to death in 53 countries, although the group said not all of them would be executed.
Amnesty said the trend toward abolishing the death penalty continued to grow, with the number of countries conducting executions halving over the past two decades.
Executions carried out in 22 countries, including Bangladesh, Belarus, Iraq, Japan, Taiwan, Uzbekistan, Vietnam
80% of executions in China
86 countries have abolished the death penalty, while 122 have abandoned executions in law or practice
74 countries retain and use the death penalty
Source: Amnesty International
"There is a global tide against the death penalty which has left us with just the hardened countries still using it," Amnesty researcher Piers Bannister said.
Mexico and Liberia are the most recent countries to abandon state execution.
However, Secretary-General Irene Khan said in a statement that the death penalty remained the "ultimate, irreversible denial of human rights".
It contravened the "essence of human values", and was often applied in a discriminatory manner, followed unfair trials or was applied for political reasons, she said.
"As the world continues to turn away from the use of the death penalty, it is a glaring anomaly that China, Saudi Arabia, Iran and the US stand out for their extreme use of this form of punishment," she added.
Ms Khan also called on Iran to ban the practice of executing juvenile offenders.
The country is a signatory to the International Convention on Civil and Political Rights, which include a promise not execute anyone under the age of 18.
However, Amnesty said it executed at least eight people last year for crimes committed when they were children, including two who were still under 18 at the time of their deaths.