The NHTSA handbook states an average male will eliminate about two-thirds of a drink per hour and the typical female burns about one-half of a drink in an hour. Why you ask?
One Reason: Alcohol has an 'affinity' for water... Swedish researcher E.M.P. Widmark found the typical male body contains 68% water while the typical female has about 55%. 
The effect: An average female has less water to distribute alcohol through her body so her BAC climbs higher than the average male on the same amount of alcohol.
What is a 'drink'? Typically a 12 ounce beer, glass of wine and shot of whiskey have the same amount of alcohol and are what is referred to as a drink.
Call a DUI attorney if charged with an alcohol related offense!