The bulk of the exonerations in 2015 came from just two states: Texas, where 54 people were cleared, and New York, with 17. The registry linked that trend to efforts by individual district attorneys in Brooklyn and in Harris County, Tex., to review questionable convictions.

Since taking office in 2014, Brooklyn’s district attorney, Kenneth P. Thompson, has overseen a broad review of potentially wrongful convictions, an undertaking that has been watched closely across the country by prosecutors, defense lawyers and inmates.

Under Mr. Thompson, the office’s conviction integrity unit has cleared 17 men, mostly of murder.

“If that same effort were put in across the country,” Mr. Gross said, “we’d find many more of these cases.”

Official misconduct played a role in 65 of the exonerations in 2015, the registry said, and false confessions were seen in 27. The most common reason inmates were cleared, in 75 of the cases, was that no crime had even occurred.

In one such case, three men were cleared of setting a fire in 1980 in Brooklyn that caused the death of a mother and her five children. The sole witness in the case was deemed unreliable, and advances in arson science showed that the fire was most likely an accident.