Though Orthodox Jews constitute the smallest of the three major denominational movements, they are much younger, on average, and tend to have much larger families than the overall Jewish population. This suggests that their share of the Jewish population will grow. In the past, high fertility in the U.S. Orthodox community has been at least partially offset by a low retention rate: Roughly half of the survey respondents who were raised as Orthodox Jews say they are no longer Orthodox. But the falloff from Orthodoxy appears to be declining and is significantly lower among 18-to-29-year-olds (17%) than among older people. (See discussion and table in Chapter 3, Jewish Identity.)Within all three denominational movements, most of the switching is in the direction of less-traditional Judaism. The survey finds that approximately one-quarter of people who were raised Orthodox have since become Conservative or Reform Jews, while 30% of those raised Conservative have become Reform Jews, and 28% of those raised Reform have left the ranks of Jews by religion entirely. Much less switching is reported in the opposite direction. For example, just 7% of Jews raised in the Reform movement have become Conservative or Orthodox, and just 4% of those raised in Conservative Judaism have become Orthodox.