When was the Zapruder film first shown to the American people?

In the Age of Viral Video, it is hard to believe but it is true: Abraham Zapruder's home movie of JFK's assassination on November 22, 1963 was not shown to the American people for twelve years after it was first taken. The film was among the most important pieces of evidence in the death of the president. But the U.S. government, the Kennedy family, or …