A record number of people exonerated for crimes they did not commit were put in prison because of official police, prosecutorial, or government official misconduct, according to new data.

Eighty-four of the 139 exonerations involved misconduct, the numbers released by the National Registry of Exonerations showed.

Overall, fewer wrongfully imprisoned people in the US were freed in 2017 than in years prior as well. The total number of people who have been falsely convicted is unknown, but last year 139 people were released, compared to 171 cases in 2016.

tance, the 2017 data showed that 96 people, in addition to the 139 individuals, were released through a “group exoneration” in Baltimore, Maryland and Chicago, Illinois after it was found that groups of police officers in both cities had been methodically framing them for drug crimes.