Catching up on my journals, I see that UA planetary scientist Ingrid Daubar and her colleagues used cameras on the Mars Reconnaissance Orbiter to determine that Mars gets hit with 100 new crater-f0rming meteorites hits per year. [right, "locations of 189 newly discovered recent impact sites on Mars. The majority of sites are in areas of high dust cover." Credit, LPSC]
The results were presented at the Lunar & Planetary Science Conference outside Houston in March.
Ref: NEW CRATERS ON MARS AND THE MOON. I. J. Daubar,1 A. S. McEwen, 1 S. Byrne, 1 C. M. Dundas1, A. L. Keske, 1 G. L. Amaya, 1 M. Kennedy2, and M.S. Robinson.3 1Lunar & Planetary Laboratory, University of Arizona, Tucson, AZ, 85721 (ingrid@lpl.arizona.edu), 2Malin Space Science Systems, PO Box 910148, San Diego, CA, 92191, 3School of Earth and Space Exploration, Arizona State University, Box 871404, Tempe, AZ, 85287.