Snapshots of the OBO Foundry ontologies for September 2009, March 2010, and September 2010. We analyzed 53 OBO Foundry ontologies at the three dates indicated in the figure. The numbers in bold next to each group of ontologies represent the number of ontologies in the group. Several ontologies are omitted from each snapshot for readability. Beginning in March 2010, the OBO Foundry designated six ontologies as OBO Foundry members, which we analyzed separately in addition to analyzing as part of the set of OBO Foundry ontologies.