Here is an overview of the use of the death penalty around the world:

At least 2,148 people were executed in 22 countries last year, according to Amnesty International.

Ninety-four percent were killed in four countries: China (1,770), Iran (94), Saudi Arabia (86) and the United States (60). China does not publish full official statistics on executions. Amnesty International estimates 1,770 were executed in 2005.

There are 125 countries that have abolished the death penalty in law or practice. About 70 countries and territories retain and use it, although the number that actually execute prisoners in any one year is smaller.

The number of countries carrying out executions dropped for a fourth consecutive year in 2005. Over the past 20 years, the number has halved.

Singapore has hanged about 420 people since 1991, mostly for drug trafficking. This gives the city state of 4.4 million the world's highest execution rate per capita.