That’s up from the 100 million number the company announced last year around the same time, as the then current number of activations. At the time, Google said it was seeing 400 million activations daily, meaning the number of daily activations has gone up two-and-a-half times.
For comparison, earlier this month Apple said it had sold 365 million devices, overall. That doesn't necessarily add up to 365 million "active" iOS devices, just as Google's number doesn't necessarily mean 400 million "active" Android devices, but considering how rapid Android's rise has been recently - quadrupling in about a year - common sense would imply that Android has a larger current active installed base.
Hugo Barra, a product management director of Android at Google, also pointed out Android’s growth in developing nations like Brazil and India. In those locations, it would obviously be the more affordable choice due to the open source nature of Android as well as the multiple form factors and OEMs building handsets.