In 2013 the White House Office of Science & Technology Policy (OSTP) released a memo directing certain federal agencies (those with more than $100M in R&D expenditures) to "develop plans to make the published results of federally funded research freely available to the public within one year of publication and requiring researchers to better account for and manage the digital data resulting from federally funded scientific research." See full memo titled "Increasing Access to the Results of Federally Funded Scientific Research" here (PDF). Many funding agencies now require the inclusion of a data management plan in grant proposal submissions.
This chart is a visualization based on a crowd-sourced Google Spreadsheet that consolidates guidelines from US funding agencies stemming from the Whitehouse Office of Science and Technology Policy's (OSTP) 2013 memo to expand public access to the results of federally funded research. The chart provides an overview of each agency's compliance with policies that are intended to "[open] government data resources" by working towards public access for all research outputs supported by federal funding. (Process Toward Opening Government Data Resources. The White House, 16 Aug. 2013. Web.)