Story highlights

A majority of recent pardons have been granted in the final year of a president's term

Many pardons are granted in groups of a dozen or more

Most people who receive pardons average two decades since they were convicted

Washington CNN  — 

It was an atypical pardon from an atypical president.

When President Donald Trump granted his very first pardon to Arizonan former sheriff Joe Arpaio, he bucked process and precedent by circumventing the Department of Justice’s unit dedicated to making recommendations on such requests.

But he also bucked decades of precedent for how recent pardons have nearly always been granted: a majority have come in the last year of a president’s term, they usually come in groups of a dozen or more and they cancel convictions averaging more than two decades old.

Trump’s pardon of Arpaio marks one of the earliest pardons in a president’s term and one of the only pardons granted alone, according to a CNN analysis of Department of Justice data ranging back nearly three decades.

And we turned that data into a chart that shows how, historically, this pardon sticks out in all three major areas: numbers of years into a president’s term, number of pardons issued at once and time since the conviction or sentencing.

The average time since the person in each group was sentenced runs up the left side, while the number of years into each term runs along the bottom. The size of each bubble represents the number of individuals in each group of pardons.

Other unique pardons that stand out in the chart include Barack Obama’s pardon of four people before trial as part of a hostage deal with Iran, Bill Clinton’s pardon of a now-disputed crime in 1881 by the first African-American to graduate from West Point, and George H.W. Bush’s nine pardons that came during August of his first year as president.

“He’s done a great job for the people of Arizona. He’s very strong on borders, very strong on illegal immigration,” Trump said at a press conference on Monday afternoon, justifying his pardon of the controversial sheriff who was convicted of criminal contempt last month. “He is loved in Arizona. I thought he was treated unbelievably unfairly.”

Republican House Speaker Paul Ryan, as well as both GOP Senators from Arizona, joined Democrats in criticizing Trump’s decision to pardon Arpaio, who was a political ally during his presidential bid.

Trump is just the third president in the last 40 years to use his pardon power during their first nine months. (Data for previous presidents is sparser, but Ronald Reagan pardoned only two people in his first nine months and Jimmy Carter pardoned no one in that span, according to the DOJ.)

More than half of the pardons granted over the last three decades came from outgoing presidents in the final year of their tenures.

Most pardons are granted following a recommendation and rigorous scrutiny from a special office in the Department of Justice. They are typically granted at least five years after conviction – and are based on post-conviction character, the seriousness of the crime and demonstrations of remorse and responsibility, according to DOJ guidelines.