Quoting the Mar 2000 60 Minutes Article:
She says she was shocked to hear the voice of U.S. Sen. Strom Thurmond (R.-S.C.) on a surveillance headset about 20 years ago. "To my knowledge, all (the intercepted voices)...would be...Russian, Chinese... foreign," she tells Kroft. 20 years ago from March 2000 puts it into either the Carter or Regan administration, not Clinton's.