What does D&D Deduction % mean?

Answer 1

On June 14, 2001, the U.S. Federal Court of Appeals ruled that an obligation to pay future decontamination and decommissioning (D&D) assessments could be deducted in advance of payment because the liabilities were fixed in 1992.

Read this article for the details:
http://www.mwe.com/index.cfm/fuseaction/publications.nldetail/object_id/9DC40BC9-096E-4371-A708-9C9F6C8A3230.cfm

Answer 2

In reference to what??? Probably depletion and depreciation