Religious and traditional Israeli Jewish populations are on the rise while the secular population is shrinking drastically, according to a survey released Thursday by the Israel Democracy Institute's Guttman Center. Israelis who say they do not observe religious traditions have become fewer, especially over the past decade, making up just a fifth of the population in 2007, according to the survey conducted by Eliyahu Sapir, a doctoral student in Political Science at Hebrew University. In contrast, in 1974, one year after the Yom Kippur War, 41% of Israelis said they were secular. Meanwhile, over the past three decades more and more Israelis have defined themselves as religious or traditional. From about a fifth of the population in 1974, the proportion of those who say they are strict observers of religious traditions has now grown to a third. The number of moderately traditional Israelis has also grown, albeit not as quickly as the religiously observant, from a low of just 38% of the population to about half. The survey was carried out by telephone among 1,016 Israeli Jews. The research was supervised by Professor Asher Arian. Sapir said that he and Arian, who did not make an empirical inquiry into the reasons behind their findings, were surprised by the gradual spread of religiosity over the decades. "Based on social science studies in similar fields, we expected sudden peaks of religiosity at times of military confrontations or other crises and valleys during more stable times," said Sapir. "But, surprisingly, there has been a gradual spread of religiosity and traditionalism over the years regardless of changes that the Israeli society underwent." Sapir added that the gradual rise in the number of religious Israelis over the past three decades is definitely due in part to higher natural growth among the religious and the traditional. Another big surprise for Sapir and Arian was the strong correlation between age and religiosity. The survey found that more young Israelis were religious than old ones. A full 39% of Israelis under 40 said they were religious, compared to 32% aged between 40 and 49 and 30% aged 60 or over. "We assumed that as people got older they became more conformist and as a result there was a higher chance they would be religious." Sapir said, admitting that in Israel religious observance might be considered a rebellion against mainstream secular norms, which would explain the findings. But he added that he had no empirical evidence to back this up. Most Sephardi Jews (56%) said they were religious while only a small minority of Ashkenazi Jews (17%) defined themselves as such. Sapir said that he had expected the correlation between Sephardi Jews and religiosity to be weaker, especially as Sephardim integrated more fully into Israeli society. The vast majority of religious Israeli Jews said they were politically right-wing, with 71% defining themselves as such compared to just 7% who said they were left-wing. Among secular Israelis too, more defined themselves as right-wing (43%) than left-wing (27%). Some 21% of religious Israelis, 29% of traditional Israelis and 30% of secular Israelis defined themselves as centrists.