Amazon.com employs more than 100,000 humans -- and 15,000 robots, more than 10X as many robots as the company deployed in mid-2013, and 50% more than CEO Jeff Bezos predicted six months ago, notes analyst Shawn Milne at Janney Capital Markets in Philadelphia in a report to clients today.

The company has added robots at its new warehouse in Robbinsville, Mercer County, N.J.; and others in Tracy and San Bernardino, Calif.; Ruskin, Fla.; Fort Worth; and Sumner, Washington, and a few other sites among its scores of U.S. plants. Amazon's been using robots at least sincde its  2010 purchase of Qdisi/Diapers.com (founded by Bucknell grad Mark Lore) and especially since its 2012 purchase of robot-maker Kiva.

Robots cost around $20,000 each. Compared to $14 an hour humans, Milne says Amazon claims its robots "pick 2 to 3 times faster," improve productivity by 20%, enable Amazon to do 50% more work in a given warehouse area (because robots can work in "narrower aisles"), and cut packing time "from 19 mintues to 15 minutes per order," for total savings of up to 40% per order.

Add it all up and Amazon will be able to save $450M to $900M/year, by Minle's count, or employ at least several thousand fewer workers for the same production.

The company will still need many thousands of warehouse workers, Milne adds: "Not all units can be handled by Kiva," and humans are still more efficient for adding hours during the holiday rush, when Amazon demand doubles.