Daily Digit: It’s not a mood swing — adolescents are suffering from depression.

Daily Digit is the story behind the numbers that make our world work. Today we’re looking at the number of adolescents in the U.S. who have experienced depressive episodes. An estimated 3.1 million adolescents in the United States have experienced depression, which is roughly 13% of the U.S. population aged 12-17. Depression is more common among females than males, and highest among kids identifying with two or more races. It’s highest among high schoolers and peaks in 16- and 17-year-olds. Sixty percent of those affected do not receive any treatment. If you or anyone you know is feeling depressed, call the National Suicide Prevention Lifeline at 800-273-8255.