Probably a familiar question if you work with NIH funded researches and authors. Once a paper is made publicly available in PubMed Central (PMC), researchers, medical professionals, students and the general public can obtain the full text of the paper at any time.
Through the National Institutes of Health Manuscript System (NIHMS), you can find data on the number of users accessing an author’s paper each month. This data is available for any author manuscripts associated with a users’ NIHMS account. (Note: Statistics are limited to PMC usage and do not include access from the publisher site or anywhere else the paper may have been posted.)
Click here to read all about the NIHMS system, how to setup an account: http://goo.gl/fe7gIJ