The U.S. Energy Information Administration (EIA) publishes data on the quality of crude oil produced in the United States:
EIA also publishes the sulfur content and API gravity of crude oil imported into the United States, along with the volume, source country, and name of the processing facility (refinery) that received the oil, in the data file for the Company Level Imports. Columns M and N in this data file have the sulfur and API gravity data.
EIA has an analysis of the quality of crude oil produced in different regions of the United States in U.S. Crude Oil Production to 2025: Updated Projection of Crude Types.
Last updated: December 3, 2018