too bad for your limited resources:
Papal infallibility has been exercised far more than two times. In fact, it had been used many times prior to 1870, when it was defined by the First Vatican Council. This was the clear understanding of the council, as shown–for example–by reading the later Archbishop Gasser’s relatio to the council fathers. This was a briefing given to the bishops at Vatican I to ensure a common understanding of the proposals regarding papal infallibility they were voting on. It is reprinted in the excellent book The Gift of Infallibility (which is the best book on the subject), and in the course of the relatio, Gasser alludes to the numerous times papal infallibility had been used before the Council.
Papal infallibility continues to be widely used. In fact, the current pontiff has used it more than any of his predecessors. The reason is that papal canonizations of saints are infallible.