The National Registry of Exonerations posted its 1,000th name, that of Lawrence Williams, Friday, registry editor Samuel Gross said in a statement released Monday.
The New York man had been jailed for two years for assault in a case of mistaken identity. The Kings County District Attorney's office cleared him after a special investigation.
"Conviction integrity units" have been created by prosecutors around the country to prevent and reverse false convictions, said Gross, a professor at the University of Michigan Law School.
The registry began May 21 with 891 exonerations and new cases have been added at the rate of about five a week, he said.
Of the new cases, only 22 occurred during that period, with the rest exonerated months or even years before, Gross said. The state with the most number of exonerations is California with 120, he said. Illinois and Texas are second with 111 each. New York follows with 101.
The registry, which provides detailed information about all known exonerations in the United Sates since 1989, is a joint project of the UM law school and the Center on Wrongful Convictions at the Northwestern University School of Law.