Driven by family problems (ranging from arguments to abuse), drug abuse, sexual or physical abuse, financial pressures and a growing number of single-parent families, approximately half a million adolescents are running away from or being forced out of their homes every year in the US. In 1989, in the UK the number of runaways was officially estimated at approximately 100,000 cases, most commonly 15 year-olds. Half returned within 24 hours, a further quarter after 72 hours, and 3% were away for 10 days or more. About 40% of those who stay away from home enter the care of a municipal authority and about half of these repeatedly go missing. Around 7% get involved in prostitution and 20% with drug abuse. A study in 1993 indicated that one in seven young people in Leeds left home for a least one night before the age of 16, namely six times more than previous official estimates.