The 43 executions in 2012 was 56 percent less than the peak in 1999 and equaled last year's total, the report, released Tuesday, said.
Twenty-nine states either have no death penalty or have not carried out an execution in five years, the report said.
The number of new death sentences in 2012 was the second lowest since the death penalty was reinstated by the U.S. Supreme Court in 1976, the center said. Seventy-eight people were sentenced to death in 2012, a 75 percent drop since 1996, when 315 capital punishment sentences were handed down.
Many death-penalty states that have histories of high use had no new death sentences or no executions in 2012. North Carolina, South Carolina, and Virginia reported no death sentences and no executions, while Alabama, Georgia, Louisiana and Missouri reported no executions were performed.
"Capital punishment is becoming marginalized and meaningless in most of the country," said Richard Dieter, the center's executive director and report author. "In 2012, fewer states have the death penalty, fewer carried out executions, and death sentences and executions were clustered in a small number of states. It is very likely that more states will take up the question of death penalty repeal in the years ahead."
Texas, Oklahoma, Mississippi, and Arizona were responsible for more than 75 percent of executions nationwide, the report indicated.
Four states -- Florida, California, Texas, and Alabama -- accounted for two-thirds of the nation's death sentences, the report said.