If you do not have a silent post page set up already and have not been collecting transaction data, the only way to retrieve the transaction information is to use the Transaction Details API. Problem is, the only way to tell which ones are subscriptions is this:
When the Silent Post URL feature is enabled, name/value pair responses for both ARB transactions and all other non-ARB transactions will post to the specified URL. To determine which transaction responses are for ARB payments, you can parse the response for the x_subscription_id (Subscription ID) and the x_subscription_paynum (Subscription Payment Number) fields. These fields are only returned in ARB subscription transaction responses.
According to the documentation, those fields are not returned in the Transaction Details API, though I don't know if that's true or someone just left them out of the documentation. Short of that, you would have had to pass an internal account number or something so they can be matched up / separated from one another. Have you been doing that?
I guess the short answer is that this is easily doable if the solution only has to work going forward. If it has to work retroactively, then things may get rather complicated depending on how your system has been set up. If your site uses an SQL database of some sort (MySQL, etc.) then I can probably program something for you, figure $200-$300 depending on how detailed the statistics you want to generate are, or if you have Quickbooks, you can just download a file from your interface every now and then (haven't tried this, since I don't have Quickbooks, so I don't know what the data looks like).
