The more I read this document, the more confused I get. I am most curious about the proportion of this jet fuel being burned by helicopters. The document has

The more I read this document, the more confused I get. I am most curious about the proportion of this jet fuel being burned by helicopters. The document has some information about rotorcraft, confirming that helicopters are included (though rotorcraft also includes petrol-burning gyroplanes...) Page 5 for instance lists rotorcraft. But page 5 is confusing to me; has the categories 'single engine', 'multi-engine', 'turboprop', 'turbojet', 'rotorcraft', etc. Are aircraft being double-counted in these categories? Is a single-engine turboprop plane counted twice, in both the turboprop and single-engine categories? Is a Bell 206, a multi-engine turboshaft helicopter, counted as multi-engine, rotorcraft... and also turbojet/turboprop? There is no category on this page for turboshaft aircraft. Maybe the nature of these classifications is clear to a pilot, but they aren't to me. Page 7 breaks down total operations into the categories jet/piston/turboprop, and seems to have piston operations as about 1/3rd of the total. 1/3rd is a far cry from 1/9 ratio suggested by 209 million gallons of avgas vs 1.8 billion gallons of jet fuel. Here is my suspicion: that difference comes from turboshaft helicopters. Typical turboshaft helicopters burn many more gallons of fuel per hour than other forms of GA aircraft. Also a nitpick: GP mentioned amateur pilots, but many general aviation pilots are doing it professionally. I would wager most helicopter-hours are probably being flown by professional pilots. For instance, all the helicopters being flown for news stations and police departments have professional pilots and fall under general aviation.