How many church members are there in the world?

No one knows, as your Sunday school teacher may already have told you.

So the job of counting church members falls to frailer institutions like church offices or communion headquarters. Each year more than 200 American and Canadian Christian communions report their numbers to the Yearbook of American and Canadian Churches, which adds them up.

The 2009 Yearbook has announced the result. There are 146,663,972 church members north of the Rio Grande.

Give or take. The actual figure, according to the Rev. Dr. Eileen W. Lindner, Yearbook editor, depends on who's doing the counting and how.

For some churches, "membership accrues to children brought for baptism," Lindner writes in an essay titled "The Meaning of Membership: Reassessing the Counting of Sheep."

"Others confirm membership at the time a youth confirms the intention to follow in the faith tradition of baptism. Still others rely primarily upon adult affirmation of faith or of a born-again experience in adulthood."

That makes comparisons "quite difficult," Lindner says. Some churches count active and inactive members while others keep all baptized infants on their rolls.

"Many church members relocate, affiliate with other churches, lose interest in church membership or relocate permanently" without deleting their membership, Lindner writes.

Untold numbers of college students and military personnel keep their local membership active long after they have moved away, as do adults who retire in communities far away from their home churches.

Some traditions, Lindner writes, estimate the number of members in their churches. Many Orthodox and African American communions base their estimates on the ethnic or racial population in neighborhoods.

"Those accustomed to the assembling of such data know that development of annual reports is a rather imprecise art," Lindner writes. "This lack of precision derives, in part, from the wide diversity of practice among the churches concerning the definition of 'membership.'"

Whether or not church membership remains a common measure of church vitality, she said, the Yearbook will continue to monitor and report on developments. "More research will be needed if we are to follow the variety of responses to the issues of membership and affiliation in American church life and gain a deeper understanding of the meaning of church membership."

This story is provided by Worldwide Faith News.