Contact the editors
Corrections, newer sources and questions about the method are all welcome.
The editors’ address is being set up and will appear here.
Corrections
Tell us the page, the claim and the source that shows it is wrong or out of date. We check it, fix the page if needed and log the change.
Newer figures
If you have published a rig price, a dataset paper with collection times or a pay range for operators, send the link. We use published, linkable material only, and we do not accept payment for inclusion.