Exorcism
In Catholic practice the person performing the exorcism, known as an exorcist, is an ordained priest. The exorcist recites prayers according to the rubrics of the rite, and may make use of religious materials such as icons and sacramentals. The exorcist invokes God—specifically the Name of Jesus—as well as members of the Church Triumphant and the Archangel Michael to intervene with the exorcism. According to Catholic understanding, several weekly exorcisms over many years are sometimes required to expel a deeply entrenched demon.
Gabriele Amorth
In October 2000, it was reported he had performed over 50,000 exorcisms (which ranged from "a few minutes" to "several hours" in length). In March 2010, he said that the number had increased to 70,000 . By May 2013 he said he had performed 160,000 exorcisms in the course of his ministry. Note that according to Father Amorth, each exorcism does not represent a victim of possession, but rather each exorcism is counted as a prayer or ritual alone, and some possession victims required hundreds of exorcisms.