Table. National Institutes of Health Manuscript Submissions (NIHMS) that will be freely available on PubMed.
This is newsworthy today, because the policy was set to expire but recently made permanent as part of the 2009 Consolidated Appropriations Act! The spike in submissions in 2008 is due to a Jan 2008 public access policy enacted April 2008. This type of dramatic year-to-year change, in trees, would show up as bigger growth rings.
For more in depth reporting see the Science Commons blog.