According to a 2001 UNICEF survey, in 10 out of 12 developed nations with available data, more than two-thirds of young people have had sexual intercourse while still in their teens. In Denmark, Finland, Germany, Iceland, Norway, the United Kingdom and the United States, the proportion is over 80%. In Australia, the United Kingdom and the United States, approximately 25% of 15-year-olds and 50% of 17-year-olds have sex. In a 2005 Kaiser Family Foundation study of US teenagers, 29% of teens reported feeling pressure to have sex, 33% of sexually active teens reported "being in a relationship where they felt things were moving too fast sexually", and 24% had "done something sexual they didn’t really want to do". Several polls have indicated peer pressure as a factor in encouraging both girls and boys to have sex.