Query: In what year did Liebman announce his findings?
Context: James Liebman, a professor of law at Columbia Law School, stated in 1996 that his study found that when habeas corpus petitions in death penalty cases were traced from conviction to completion of the case that there was "a 40 percent success rate in all capital cases from 1978 to 1995." Similarly, a study by Ronald Tabak in a law review article puts the success rate in habeas corpus cases involving death row inmates even higher, finding that between "1976 and 1991, approximately 47 percent of the habeas petitions filed by death row inmates were granted."