VENTURA, Calif.--Since 1991, the number of unchurched has nearly doubled from 39 million to 75 million, according to The Barna Group, a company that follows trends related to faith, culture and leadership in America.

The latest study shows that the percentage of adults that is unchurched - defined as not having attended a Christian church service, other than for a holiday service, such as Christmas or Easter, or for special events such as a wedding or funeral, at any time in the past six months - has risen from 21 percent in 1991 to 34 percent today.

The study examined demographic attributes of unchurched and churched populations and found at least four significant distinctions.

Most of the unchurched are young, male, single and living in coastal regions.

Men represent only 38 percent of the born-again public.

The unchurched are also younger (median age: 38) than most U.S. adults (median age: 43). Born-again adults are substantially older than either group (median age: 46).

While one-quarter (26 percent) of American adults are single-never-married, nearly two-fifths(37 percent) of the unchurched fit that definition.

The unchurched are also attracted to the coastal regions of the nation. Although just four out of ten adults (42 percent) live in the Northeast or West, more than half of the unchurched (51 percent) live there.

In fact, the two largest states in the nation - California and New York - contain 18 percent of the nation's residents, but one-quarter of its unchurched adults (23 percent).

Other differences between the unchurched and the churched included less Bible reading, prayer and salvation through Jesus Christ.

However, Barna reported that while about half of the churched population has accepted Jesus Christ as their savior, one out of every six unchurched adults (17 percent) has done so, as well.

The study revealed that the unchurched are also less likely to participate in elections, less likely to donate to non-profit organizations, and less likely to use media or to engage in community activities.

"The unchurched are more likely than others to be somewhat isolated from the mainstream activities of the society in which they live," said director of the study, author and researcher, George Barna.

Barna also described the group as "non-committal" and "independent." He noted that to unchurched people, embracing church life is "both counter-cultural and counter-intuitive."

"Unchurched people are not just lazy or uniformed," the researcher continued. "They are wholly disinterested in church life -- often passionately so.

Barna said nothing churches do to attract this unchurched group can compete with what the world already offers them, except a transformational relationship with God.

"Millions of young adults are more interested in truth, authenticity, experiences, relationships and spirituality than they are in laws, traditions, events, disciplines, institutions and religion," Barna said.

The data for the annual tracking survey on church attendance by The Barna Group is based upon telephone interviews with a nationwide random sample of 1014 adults conducted in late January and early February of 2004.