You sure about that? WD40 contents from its Material Safety Data Sheet:
Aliphatic Hydrocarbon = 45-50%
Petroleum Base Oil = <25%
LVP Aliphatic Hydrocarbon = 12-18%
Carbon Dioxide = 2-3%
Surfactant = <2%
Non-Hazardous Ingredients = <10%
(Aliphatic hydrocarbons include methane, propane, butane, isobutate, ethylene, etc.)