NIH Public Access Policy/PMCID Numbers
NIH Public Access Policy Details
The NIH Public Access Policy implements Division G, Title II,  Section 218 of PL 110-161 (Consolidated Appropriations Act, 2008).  The law states:

The Director of the National Institutes of Health shall require that all investigators funded by the NIH submit or have submitted for them to the National Library of Medicine’s PubMed Central an electronic version of their final, peer-reviewed manuscripts upon acceptance for publication, to be made publicly available no later than 12 months after the official date of publication: Provided, That the NIH shall implement the public access policy in a manner consistent with copyright law.

In-accordance with PL 110-161, as a grantee, we must adhere to this mandatory policy.   Failure to do so could result in funding being withheld by NIH for any given project found out of compliance.
How to Find PMCID numbers