Amazon is banging the drum for its Amazon Appstore for Android as it launches in Europe, claiming that “customers have downloaded hundreds of millions of apps and games” from the store since its launch last year.

Want more figures? Don’t hold your breath. Amazon tends to keep its stats close to its chest, and that’s about as much as it’s saying on the performance of its app store, other than the claim that the number of developers supporting it “continues to grow quickly”.

Here’s a (sort-of) stat from the announcement: “The average In-App Purchasing transaction generates more than twice the revenue of the average paid app transaction”. Whatever that may be.

Social games developer Frenzoo is quoted in the release saying “because of Amazon’s IAP solution, our apps monetize 50% better than they do on other platforms we’re on”, but again, no details.

Meanwhile, rival developer Pocket Gems has seen “more than 16 million sessions” of its games through Amazon’s store, while ABC News generated “tens of thousands of downloads in just under a month” on the Kindle Fire tablet.

There is more speculation, too, about the about-to-be-unveiled second-generation Kindle Fire. The Wall Street Journal suggests it will be “an advertising-supported tablet that will be priced lower than similar models”, following a business model first seen with its Kindle e-readers.

CNET suggests there will be two models unveiled at Amazon’s press event next week: “a new 7-inch Kindle Fire and a slightly revamped version of the original tablet”. Perhaps the latter will be the ad-supported model.