Despite the danger of excessive internet use and the threat of bullying, most teenagers around the world are "relatively" happy with their lot, a major OECD survey showed on Wednesday.Asked to rate their satisfaction with life on a scale of 0 to 10, some 370,000 15-year-olds gave a mean score of 7.3, the Paris-based group said.The respondents were among 540,000 from 72 countries that took part in a larger survey conducted by the OECD's Programme for International Students Assessment (PISA) in 2015.The survey found great disparities between countries, with fewer than four per cent of students in the Netherlands saying they were "not satisfied" with life, a figure that rises to more than 20 per cent in South Korea and Turkey.Boys were happier overall, with 39 per cent reporting being "very satisfied" compared with 29 per cent of girls, the Organisation for Economic Cooperation and Development report said.However the gap is minimal between high- and low-achieving students.Bullying is "perhaps the most distressing threat to students' well-being," according to the study, which asked students how they felt about their achievement at school, their relationships with peers and professors, their home life and their leisure activities.In 34 of the countries studied, more than 10 per cent of the students said their classmates make fun of them several times a month.Around four per cent reported being hit or pushed several times a month, while 7.7 per cent said they were victims of physical harassment several times a year.Among those who reported frequent harassment, 42 per cent said they felt like outsiders at school.The study also warned about excessive internet use, saying more than one in four (26 per cent) of respondents spent more than six hours a day connected at the weekend, and 16 per cent said they devoted similar chunks of time online on weekdays."These 'extreme internet users' are more likely to feel lonely at school, have low expectations of further education, and tend to arrive late for school," the report said."There are no quick fixes for the risks of the digital era, but schools can create opportunities for students to use the internet more responsibly," PISA coordinator Andreas Schleicher said in the report.Sources of stress include anxiety about schoolwork and income inequality.Students believing themselves to be less wealthy than most of their classmates tend to report lower satisfaction with life, the report said.But disadvantaged students with wealthier classmates who have "pro-school attitudes and high expectations for themselves...tend to develop higher ambitions for their future," the report concluded.