Actually, I wouldn't be surprised at all, given that it seems to be the canonical on-disk data store for both Android and iOS. Whether you want to measure total uses by developers, the developers themselves, the users using it, the apps using it, the size data stored, I imagine mobile use probably swamps everything else.

For example, I probably have 20-30 sqlite using apps on my phone, if not more. And I wiped it clean when I got a new phone a few months back and have been fairly hesitant to add apps I haven't found proven use for.