This year's annual report, SOS 2011, summarizes the 19,232 new living species officially described in calendar year 2009 and includes animals, plants, algae, fungi and microbes. The Retro SOS provides a data summary of the 176,311 new living species that were discovered and described from 2000 to 2009. With a scope of 10 years, the Retro SOS allows a greater understanding of the data trends that reflect the successes, gaps, and opportunities of species exploration ? such as a notable 12.8% increase in new extant species descriptions for the time period.