Approximately 95% of those affected by anorexia are female, but males can develop the disorder as well.  In the U.S. and other countries with high economic status, it is estimated that about one out of every 100 adolescent girls has the disorder.  Caucasians are more often affected than people of other racial backgrounds, and anorexia is more common in middle and upper socioeconomic groups.  According to the U.S. National Institute of Mental Health (NIMH), an estimated 0.5% to 3.7% of women will suffer from this disorder at some point in their lives.