The proportion of American Jews whose spouses are from another religion - 31 percent - is lower than the national average for all groups (37%), according to a Pew Center survey released last year. However, if marriages between members from different Protestant sects are not counted as intermarriage, the US average is only 27%, according to the Pew Forum on Religion and Public Life's US Religious Landscape Survey released in February 2008. In any case, the rate for American Jews is set to climb, as 47% of community members who married between 1996 and 2001 married non-Jews, the National Jewish Population Survey, sponsored by United Jewish Communities and the Jewish Federation system and conducted between 2000 and 2001, found. While the US intermarriage rate climbed significantly between 1970 and 1990, it has since stabilized at around 50%, Uzi Rebhun, of the Institute of Contemporary Jewry at the Hebrew University, said on Monday. "That's kind of an uppermost threshold that Jews probably will not pass," he said. "The older people who were in-married by huge proportions - these people are going to be leaving us inexorably and the people who are now, say, in their 30s... they're going to represent a larger and larger chunk of the American Jewish population," said Prof. Eli Lederhendler, head of the Institute of Contemporary Jewry. "If you look at Jews who have married in the last five or 10 years, what proportion of those are marrying Jews versus non-Jews - that leads to the 40 to 50% [figure]." Rebhun said the increase in intermarriage among younger people had several causes: secularization of American society; Jewish social and economic advancement, which has increased interaction among Jews and non-Jews; a dispersal of American Jews from cities in the Northeast to the South and West, where there are fewer Jews; and the emphasis on multiculturalism in the US, which makes personal religious identity less important for things such as marriage. What might be more significant than intermarriage is how the children of intermarried couples are raised, he said. While Jewish parents might maintain their Jewish identity, they are less likely to pass it on to their children. According to the US Religious Landscape Survey, only Hindus at 10%, Mormons at 17% and Catholics at 22% showed lower rates than Jews of marrying outside their religion. America's largest religious group, Protestants, had an intermarriage rate of 37%.