Actually, as the article notes, the breakdown varies widely depending on deals with labels. The classic split for many fairly-run independent labels is an even 50/50 split between artist and label after expenses (to the author's credit, she mentions this--but not till the last paragraph). Of course there are still costs associated with manufacturing & distribution. But I would imagine that many Boing Boing readers listen to independent music which uses 50/50 splits, rather than major label artists like "N-Dubz and Charlotte Church," who are represented by the source for these figures.
That "5% for administering copyrights" is poorly described and probably needs unpacking. Does it mean the sound recording copyright or the songwriting/publishing copyright? In the US, 9.1cents for every track goes to the songwriter (who may or may not also be the performing artist). But the UK uses a different system. It would be lazy to suggest that this fee simply goes to useless middlemen.
It's also the case that in the UK, prices for CDs have long been generally higher than the US, which means that the breakdown of retail price works out somewhat differently.