Key facts More that 1.8 million young people aged 15 to 24 die each year, mostly due to preventable causes. About 16 million girls aged 15 to 19 give birth every year. Young people, 15 to 24 years old, accounted for 40% of all new HIV infections among adults 	 in 2008. At least 20% of adolescents will experience a mental health problem in a year, most commonly depression or anxiety. An estimated 150 million young people use tobacco. Approximately 565 young people aged 10 to 29 die every day through interpersonal violence. Road traffic injuries cause an estimated 1 000 young people to die every day.