A survey shows that ebook usage on smartphones  jumped an impressive 300% in the four months from April to July 2009.

The data comes from Flurry, a company that tracks usage of smartphone apps in a similar way to how Google tracks website metrics with its Analytics product.  The data shows active usage in the ebook category, measured by user sessions.

The survey is embedded below.

The interesting thing here is that, because Flurry measures actual usage of the smartphone apps rather than just downloads, it’s a solid indication that iPhone, Android and other smartphone users are not only downloading these ebook reader apps, they’re actually reading with them.

Flurry Smart Phone Industry Pulse July2009 Final