They didn't even manage to get the UK right. Apparently whoever made this map doesn't know that the UK is the "United Kingdom of Great Britain and Northern Ireland" and that Éire is only the bottom bit.

I wonder how that skews the figures. Are folk in NI paid more in line with GB or with Éire? I'm sure currency comes into play too, what with Éire using the euro.

NI is poorly paid. the UK as a whole is poorly paid outside of London and maybe Oxford/Cambridge and a couple of other industry specific areas.

I suspect Ireland also has the same problem, with the higher salaries being Dublin only.