(RNS) Protestants could cease to be the majority religious group in the United States within the next year and their numbers already may have dipped below 50 percent, a new study by the National Opinion Research Center says.

From 1972, when the University of Chicago-based NORC began its General Social Survey, until 1993, the Protestant share of the population remained constant, averaging 62.8 percent. It then began to show a decline, reaching 52.4 percent in 2002.

The study attributed the decline to, among other things, the fact that fewer children were being raised in Protestant homes over the past four decades. The share of people who said they were raised as Protestants dropped from 64.7 percent in 1972 to 55.7 percent in 2002.