Since it isn't clear what "number" you are talking about, thought I ask. Also, for ease of reference, here's the information on the company for the link above:

"Modular Science – Outdoor robot farming: Elon Musk may be concerned about robots taking over the world, but Modular Science just wants robots to farm our vegetables. The startup, which currently has robots out in the field (!) in Petaluma, CA, is aiming to automate 99 percent of the processes involved in vegetable farming within the next six months with their specialized farming bots. Modular Science is looking to charge $2,000 per acre, which they say is half of what farms are currently paying to for human labor."