Procedure Adolescent girls(n 2,089) aged 11-18 years(15% in year 7: age 11-12 years, 23% in year 8: age 12 13 25% in year 92 age 13-14 years, 25% in year 10: age 14-15 years, T% in year age 15-15 years, 396 in year 12, age 16-17 years, and 2% in year 13. age 17-18 were schools and colleges(making it difficult to report a response rate).