"During the first quarter of 2016, Tesla delivered over 25 MWh of energy storage to customers on four continents. Over 2,500 Powerwalls and nearly 100 Powerpacks were delivered in North America, Asia, Europe, and Africa.[33]"

https://en.wikipedia.org/wiki/Tesla_Powerwall

I don't know if those were still pilot program devices or if they've hit some level of regular production. 2500 units is still a good start.