Twenty five executions were carried out in 2018, the fourth consecutive year in which there have been fewer than 30, according to an annual US Death Penalty Information Center report released on Friday.

Since the death penalty was re-instated in the United States in 1976, the number of executions peaked in 1999 with 98. They were at their lowest in 2016 with 20.

Americans' support for the death penalty similarly peaked in the 1990s and has declined since, according to opinion polls by Gallup.

Its research reveals 56 per cent of Americans supported the death penalty in 2018 for a person convicted of murder.

Executions in 2018 were clustered in eight states: Alabama, Florida, Georgia, Nebraska, Ohio, South Dakota, Tennessee and Texas.

About half all executions took place in Texas, which carried out 13 death sentences.

Tennessee was second with three. Alabama, Florida and Georgia each had two while Nebraska, Ohio and South Dakota each carried out one.

Florida's execution on Thursday of Jose Antonio Jimenez for fatally beating and stabbing a woman during a burglary was the most recent.

Nebraska, Tennessee and South Dakota were the three states that resumed executions this year.

Nebraska's execution of Carey Dean Moore for killing two cab drivers in 1979 was the state's first execution in more than 20 years.

It was also the first time any state has used the drug fentanyl in an execution.

This year marked the first time in nearly nine years Tennessee carried out an execution.

South Dakota ended a six-year stretch without one when it executed Rodney Berget, who was convicted of killing a corrections officer during a prison escape attempt.

The DPIC report says 41 new death sentences have been imposed so far this year, the fourth straight year with fewer than 50.

Australian Associated Press