In 2005, Americans spent $11 billion treating allergies, according to figures from the Agency for Healthcare Research and Quality, a division of the US Department of Health and Human Services. This represents a significant increase to the $6 billion spent in 2000. Twenty-two million Americans went to the doctor for their allergies, at a cost of $4 billion. Prescription drugs cost another $7 billion. These figures include doctor visits and prescription medication, but do not include over-the-counter medications. Most of the increase is due to the increase in the average annual cost for treatment, which went up from $350 per person to $520 per person between the years 2000 and 2005.