It says:
"Chemical combustion: ~ a few MJ/kg • Solid Propellants: ~ 5 MJ/kg • Liquid Propellants: ~ 1 MJ/kg"
Which doesn't look right. My son (a rocketry enthusiast) tells me:
"Liquid engines have energy density between 12 and 20MJ/kg. Apparently they just left off the 0 and likely meant to put 10MJ/kg"