Young Indonesian Muslims hold conservative values but have a low observance and understanding of Islamic rituals and religious knowledge, a survey showed Tuesday. The Indonesian Survey Institute poll of nearly 1,500 respondents found that 98 percent of them disapproved of premarital sex, 99 percent did not accept homosexuality and 89 percent rejected alcoholic beverages. \"Their disagreement to have sex before marriage is very high,\" the survey jointly conducted with the Goethe Institute showed. \"Having sex before marriage is strictly forbidden and being gay or lesbian is cursed. On these issues, most Muslim youths have conservative opinions,\" it said. But the survey revealed that only 28.7 percent of respondents performed the daily five-time prayers, only 11.7 percent understood many verses of the Koran and less than 60 percent of them fasted during the holy month of Ramadan. The poll was conducted in November 2010 across the world\'s most populous Muslim country among respondents aged between 15 and 25. More than eighty percent of Indonesia\'s 240 million people are Muslims but the country\'s constitution guarantees freedom of religion.