In app purchases in Android - need some statistics

I am considering adding in-app purchase in my Android application. The idea is to make the application itself free, and ask the user to pay for some virtual goods that are required to use it (the kind of goods is region-specific, this is why it's a good idea to have it this way).

My question is rather generic: I know that in order to use in-app purchases (which were made available only a couple of months ago) a user must have version 2.3.4 or higher of Android Market Application.

Here's quote from Android in-app billing overview (http://developer.android.com/guide/market/billing/billing_overview.html):

If your device is running Android 3.0, in-app billing requires version 5.0.12 (or higher) of开发者_StackOverflow中文版 the MyApps application. If your device is running any other version of Android, in-app billing requires version 2.3.4 (or higher) of the Android Market application.

Are there any open numbers that could tell me, at least approximately, how many users (percentage-wise) have this, in order to be able to make in-app purchases? Also, will Android system prompt the user to install the latest Market Application if he/she doesn't have it, when user clicks "buy" button?

I am also considering in-app billing for a personal project and have been unable to find any accurate statistics, but there is a way to roughly deduce this percentage.

It is pretty accurate to assume that any user using Android version 2.2 has Android Market version 2.3.6. (I have verified this on many friends' phones that are still on 2.2). So 2.2 users and above are among 73.8% of android users. So that's a safe minimum, 73.8%.

To answer your second question you can see the error yourself if you try to implement in-app billing on the emulator and although it doesn't direct you to download the latest Market version, it does spawn an error saying you are not compatible.

You can also use the sendBillingRequest() method and send the CHECK_BILLING_SUPPORTED key before doing anything to make sure that the user supports in app billing and present a UI that supports this, or not.