The number of executions declined in the US this year amid drug shortages and growing concerns over the cost and fairness of death penalty cases, according to a new report from the Death Penalty Information Center (DPIC), a Washington, DC-based nonprofit organization. The annual report, published Thursday, shows that there were 39 executions carried out in the US this year, down from the 43 that were carried out in both 2012 and 2011. This marks just the second time in 19 years that fewer than 40 people were executed on US soil.

So far, 80 people have been sentenced to death this year — two more than last year, but well below the historical high of 315 death sentences handed down in 1994 and 1996. The number of death sentences issued this year is the lowest since 1976, when the US Supreme Court reinstated capital punishment.

"Life without parole... has become the alternative."

"The key reason for the decline in the death penalty has been the revelation of so many mistakes," Richard Dieter, DPIC executive director, said in an email to AFP. "Over 140 people have been exonerated and freed from death row, including another inmate in 2013." He added that these exonerations — many of which were brought about by more advanced DNA testing — have made prosecutors less likely to pursue death sentences and juries less likely to impose them.

States have also had greater difficulty in procuring drugs used for lethal injections, as pharmaceutical companies have become wary of associating themselves with capital punishment. Many lethal injection drugs are manufactured in Europe, but the European Commission imposed tough export restrictions in 2011, forcing some states to impose moratoriums or pursue untested or unregulated procedures. Under the European policy, exports of drugs used for lethal injections in the US are banned, as part of the EU's mission to abolish the death penalty worldwide.

There are currently 3,108 inmates on death row across the US, led by California (731), Florida (412) and Texas (298). Maryland repealed the death penalty earlier this year, making it the sixth state to do so in the past seven years, and the 18th overall. Public support for capital punishment appears to be waning, as well. A Gallup poll published in October showed that 60 percent of Americans support the death penalty, the lowest level in more than 40 years.

"Life without parole, which is now quite prevalent, has become the alternative to the death penalty," Dieter told AFP, "and will likely replace it completely in the future."