About: http://webisa.webdatacommons.org/451305463

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	In a first effort the amount of oil extractable from a particular deposit varies widely between 30% and 70%, depending on viscosity, porosity of the rock and other factors and averages 50%.
http://www.w3.org/ns/prov#wasQuotedFrom	bikeportland.org