Records show the exodus from the priesthood began at the end of the Second Vatican Council (1962-1965).
Pope Paul VI (1963-1978) was greatly distressed by this phenomenon but generally granted dispensations to those who requested it. Pope John Paul II (1978-2005), alarmed at the rising numbers, sought to halt this exodus by making it difficult for priests to obtain dispensations. By 2000, organizations working with priests who had left the ministry claimed the number of departures had reached 100,000.
In mid-2007, the authoritative Italian Jesuit fortnightly magazine, "La Civilta Cattolica," (Italian for "The Catholic Civilization") challenged that number in an article, published with the approval of the Vatican Secretariat of State.
It reported that 69,063 priests left the ministry between 1964 and 2004 but said 11,213 of them later returned. It revealed that these statistics were based on information provided by the bishops to the Vatican but did not clarify if the figures reflected all departures or only those who requested dispensations.
It furthermore revealed that an average of 1,000 priests had left the priesthood each year between 2000 and 2006 but that only half of them requested dispensation.
Using the most recent figures available, it reported that between Aug. 1, 2005 and Oct. 20, 2006, the Vatican had received 904 requests for dispensation, including some from deacons.
The requests came from the following countries: 185 from the United States, 119 from Italy, 60 from Spain, 59 from Brazil, 52 from Poland, 48 from Mexico, 32 from Germany, 31 from the Philippines, 29 from Argentina, 27 from India, 26 from France, 23 from Ireland, 22 from Canada and so on. "La Civilta Cattolica," however, gave no indication of how many left the priesthood without requesting dispensation.
Link (here) to the full article
Ordination to the priesthood at the Vatican (here)