The first interesting question to ask is what, in BAEC terms, is a customer?

How about somebody who is a member of the BAEC has flown BA in the last two years?

Within this group my completely off the wall guess would be 10% bronze or higher, 5% silver or higher and 2.5% gold or higher.

But there are too other interesting questions too, which are:

i) what % of journeys are made by passengers with each status level?
ii) what % of RPK are made by passengers with each status level?