The issue has received considerable political attention, despite the fact that, according to the GERS figures, it accounts for a relatively small share of Scottish income.I will not pretend to understand the fine details of how the Executive produces the regional accounts before it works out Scotland's share of the total figure, but I am considering the profits of the Royal Bank of Scotland, which is a high-profile Scottish company, and the estimated £2.5 billion in corporation tax that is paid.