Number of New Death Sentences in 2015 Lowest in More Than 40 Years

A steady decline of executions in the United States reached a new low in 2015, which also saw the lowest number of death sentences handed down by states and the federal government since the period between 1972 and 1976, which followed a Supreme Court decision that temporarily imposed a moratorium on capital punishment.

There were only 28 executions this year, the lowest number since 1991, and 49 new death sentences — a 33 percent decline from last year, according to the Death Penalty Information Center's annual report released Wednesday.

The rates of death penalty use have generally trended downward across the board since reaching a high of 98 executions in 1999. Even in Texas, Missouri, and Georgia — three states that carried out 86 percent of executions in 2015 — the numbers fell.

The report said that nearly two-thirds of the new sentences were in just 17 counties, mainly in California and Florida, which are two of the country's 31 states that still have the death penalty on the books.

Part of the reason for the decline has been litigation over drugs used to carry out lethal injections following several botched executions.

In June, the Supreme Court upheld the lethal injection process used in Oklahoma. Three death row inmates had challenged the use of the sedative midazolam, which is routinely injected into prisoners being put to death in order to first knock them out, so that they cannot feel excruciating pain when the other two drugs enter their bloodstream. Lawyers for the inmates argued that midazolam could not maintain a coma-like unconsciousness, potentially leaving the inmates in intense pain when drugs that cause death are administered.

Related: Supreme Court Rules States Can Use Controversial Lethal Injection Drug

The petitioners also cited instances in which midazolam failed to work during executions, including the deaths of Dennis McGuire in Ohio, who gasped for 25 minutes before dying, and Joseph Wood in Arizona, who took nearly two hours to die.

Before the case was decided, several states, including Florida, had put executions on hold. Florida put two inmates to death in 2015 compared with eight in 2014. Robert Dunham, executive director of the Death Penalty Information Center, said that "there clearly was some effect" from the Supreme Court case and other disputes on the number of executions surveyed in his organization's report.

Oklahoma and other states have stood by the use of midazolam, which is relatively easy to buy from local manufacturers, as opposed to other commonly-used drugs in lethal injection cocktails that are harder to come by since many drug companies in the US and abroad stopped supplying prisons for ethical reasons and over controversy surrounding capital punishment.

The shortage of drugs has prompted states to start formulating their own largely untested drug combinations, which led to a series of botched executions and forced 32 states to reexamine their execution procedures.

While some states sought to reinstate back-up alternate methods of execution like the electric chair or firing squads, others sought to put shield laws in place to prevent the press and public from knowing details about the drugs being used, including the names of the drug manufacturers and distributors.