I highly doubt the chart is counting the content of alcohol in the drinks consumed. It's most likely just counting how large the sales of alcoholic beverages are, no matter if it's 5% beer or 98% everclear.

An average of 4.76 gallons worth of alcoholic beverages per person in NH. May make it seem low, but NH only has a population of about 1.3mil, whereas PA with lower sales per person has more than 10x the population.