VATICAN CITY (RNS) The Vatican has asked U.S. Catholic bishops to fund a $1.1 million investigation of American nuns ordered by church authorities in Rome.

“We have a projected budget of $1,100,000 for the three years which the total work of the apostolic visitations will require,” Cardinal Franc Rode, head of the Vatican’s Congregation for Institutes of Consecrated Life and Societies of Apostolic Life, wrote in a July 14 letter to bishops, first reported by the National Catholic Reporter.

“I am asking you, my brother bishops, for your help in offsetting the expenses which will be incurred by this work for the future of apostolic religious life in the United States,” Rode added.

The Vatican in January announced an “Apostolic Visitation” of U.S. women’s religious orders, the first review of all 400 communities of American women religious, which include a total of 68,000 members.

The investigation was prompted by a steep decline in the number of women entering the Catholic sisterhood in the U.S. Between 1945 and 2000, the number of religious sisters in the U.S. dropped by 54 percent, from 122,159 to 79,876, according to Georgetown University’s Center for Applied Research in the Apostolate.

The U.S. Conference of Catholic Bishops, which runs a popular yearly fundraiser for retired nuns, learned of the investigation just hours before it was announced on Jan. 30.

The visitation is running parallel to a separate Vatican investigation of the leadership of American women’s religious congregations. That investigation seeks to ensure leaders’ fidelity to Catholic teaching on controversial questions of ecumenism, homosexuality and an all-male priesthood.

The Vatican is also conducting a probe of the Legionaries of Christ, a growing conservative movement in the church, after recent revelations that its late founder fathered at least one illegitimate child, and long-standing accusations that he sexually abused boys and young men under his authority.