Ninety-eight federal inmates will return home sooner than expected after President Barack Obama commuted their sentences on Thursday, part of a clemency push that has sped up dramatically in Obama's final months.

All told, Obama has cut short sentences for 872 inmates, including 688 this year. The figure is higher than the number commuted by the previous 11 presidents combined, and the White House said more commutationswere coming before Obama leaves office in January. Of the latest batch, 42 had been serving life sentences, the White House said.

Neil Eggleston, Obama's White House counsel, said it was important to remember that "there are personal stories behind these numbers."

"These are individuals — many of whom made mistakes at a young age — who have diligently worked to rehabilitate themselves while incarcerated," Eggleston wrote in a blog post.

Almost all the prisoners had been convicted of nonviolent drug crimes — mostly involving cocaine or methamphetamine. Some were also serving time for firearms violations in connection to drug trafficking, possession or sales. Almost all are men who come from every corner of the U.S.

Though Obama granted fewer commutations earlier in his presidency, he's frequently been granting clemency to large groups of individuals this year. Only a few weeks ago, he commuted another 102 sentences of mostly nonviolent drug offenders.

Obama's order doesn't set all the prisoners free right away. Many of those receiving commutations won't see their sentences end until early next year or even as late as October 2018, long into the next president's term.

Alberto Lopez of Gardner, Massachusetts, had been serving a life term plus six years' supervised release after being convicted of possession and conspiracy charges related to distribution of heroin and cocaine. Lopez's term will instead expire on February 24, 2017 — almost exactly one month after Obama leaves the White House.

Obama's bid to lessen the burden on nonviolent offenders reflects his long-stated view that decades of onerous sentencing requirements put tens of thousands behind bars for far too long. Obama has used the aggressive pace of his commutations to increase pressure on Congress to pass a broader fix while using his executive powers to address individual cases where possible.

Yet Obama's calls for greater clemency have occasionally drawn criticism from opponents who say he's too soft on crime. Donald Trump, the Republican presidential nominee, has warned Americans that their safety could be at risk because of Obama's move to set prisoners free ahead of schedule.

Though both parties in Congress have called for a criminal justice overhaul, momentum has mostly petered out, creating dim prospects for a legislative breakthrough during Obama's final months. The inability of Republicans and Democrats in Congress to find consensus even on an issue they agree needs fixing reflects the charged political climate of the election year.

Obama has been calling for years for phasing out strict sentences for drug offenses, arguing they lead to excessive punishment and incarceration rates unseen in other developed countries. With Obama's support, the Justice Department in recent years directed prosecutors to rein in the use of harsh mandatory minimums.

The Obama administration has also expanded criteria for inmates applying for clemency, prioritizing nonviolent offenders who have behaved well in prison, aren't closely tied to gangs and would have received shorter sentences if they had been convicted a few years later.