The USCCB's office for media relations has just released a statement about the nuns' statement. The office points out that the signers of the letter don't even come close to representing American sisters:
Washington—A recent letter from Network, a social justice lobby of sisters, grossly overstated whom they represent in a letter to Congress that was also released to media.
Network’s letter, about health care reform, was signed by a few dozen people, and despite what Network said, they do not come anywhere near representing 59,000 American sisters.
The letter had 55 signatories, some individuals, some groups of three to five persons. One endorser signed twice.
There are 793 religious communities in the United States.
The math is clear. Network is far off the mark.
Sister Mary Ann Walsh
Director of Media Relations
United States Conference of Catholic Bishops