The results are from the NASA-UC Eta-Earth survey that we have been conducting over the past 5 years at Keck Observatory.
The results have quickly made their way out into the realm of popular science. Here's my favorite:
"We studied planets of many masses - like counting boulders, rocks and pebbles in a canyon - and found more rocks than boulders, and more pebbles than rocks. Our ground-based technology can't see the grains of sand, the Earth-size planets, but we can estimate their numbers," says Andrew Howard, boss scientist of the team conducting the study.So there you have it, from the Boss Boffin himself :)