Lack of miracles at Lourdes?

Since pilgrims have been going to Lourdes it is claimed that 65 people have been miraculously cured out of an estimated 100 million visitors. Three of these were patients suffering from cancer.

Compare this with the estimates for spontaneous remission of cases of cancer. 1 person in 10,000 to 100,000 will just get better for no known reason.  (Maybe someone prayed extra hard for them?  Or maybe they just got better.)

Even with the most conservative assumptions about the proportion of Lourdes pilgrims who would be suffering from cancer, it seems that the number of remissions is far below the rate of spontaneous remission.