The U.S. Catholic population stood at 58.9 million in 2010, according to a new census of religious congregations.The number of Catholics is lower than the 62 million Catholics reported in 2000, but the difference is due to a change in the way data was collected during this go-round, said Cliff Grammich, a researcher working for the Glenmary Research Center who compiled statistics from 20,589 parishes, missions and other places with regularly scheduled weekend Masses.
The 2010 U.S. Religion Census: Religious Congregations and Membership Study released May 1 showed that the number of Catholics is three times that of the country's second largest religious body, the Southern Baptist Convention, with nearly 19.9 million members.
Sponsored by the Association of Statisticians of American Religious Bodies, the study is conducted every 10 years and coincides with the once-a-decade U.S. census. It also collected data from Protestant, Jewish, Muslim, Hindu, Buddhist and other religious congregations.
Grammich told Catholic News Service that he analyzed statistics provided by individual parishes on the number of registered households, registered individuals, infant baptisms, burials and Mass attendance to arrive at the final count. In earlier studies, less specific data was sought from individual dioceses rather than from parishes, he said.
"The counts are the best that could be supported by religious data, sacramental statistics and survey data," Grammich explained.
The new study indicates a Catholic population that is significantly lower than two other oft-cited sources that track the U.S. Catholic population. The Official Catholic Directory for 2010 reported 68.5 million Catholics with data collected from individual dioceses. The 2010 General Social Survey of the National Opinion Research Center estimated there were 77.9 million American Catholics based on percentages applied to the entire U.S. population.
Grammich explained in a statement released by Glenmary Research Center with the statistics that the survey's findings are based on the canon law definition of a Catholic "as someone who is linked with the Catholic community through baptism and burial."
Overall, 150 million Americans --- 48.8 percent of the population --- were associated with the 236 reporting religious bodies.
Catholic parishes in the Northeast and north central states reported the greatest losses in population. Grammich attributed the decline to the number of deaths outpacing infant baptisms, especially in northeastern dioceses.
By region, the Northeast maintained the highest number of Catholics at 18.3 million. Elsewhere, 13 million Catholics lived in the north central region, 12.6 million in the South and 14.9 million in the West.
Other census findings include:
--- Populations in urban areas of the Northeast and Midwest declined while it grew in the South and West; regionally, the number of Catholic churches by region remained more stable.
--- Nearly two-thirds (65 percent) of Catholics were in metropolitan areas with at least 1 million residents, compared with 69 percent in 2000.
--- By state, the Catholic population ranged from 3.5 percent in Tennessee to 44.9 percent in Massachusetts.
--- The number of Catholics grew in 19 states and increased by 10 percent or more in 10 states: Alabama, Delaware, Georgia, Nevada, North Carolina, Oregon, South Carolina, Tennessee, Utah and Virginia.
--- The size of parishes varied widely, with the average parish in California having 7,782 members compared with 489 members in the average Alaskan parish.
--- The number of Catholics declined by at least 10 percent in 17 states: Indiana, Kentucky, Louisiana, Maine, Maryland, Michigan, Missouri, Montana, New Hampshire, New Mexico, New York, Ohio, Rhode Island, South Dakota, Vermont, Wisconsin and Wyoming.
--- Catholic churches, missions or communities are located in 2,960 of the nation's 3,143 counties, more than any religious body except the United Methodist Church, which claims a presence in 2,991 counties; the United Methodist population totaled 9.9 million people.