Best you look at the actual 'key figure' - paid up capital.
And read the small print...
(from the article you linked to)
"Non-Euro area NCBs are required to pay up only a very small percentage of their subscribed capital"
Keep on digging that hole of yours, filly
Edit: I'll do the maths for you
Add the paid up figures of...
Eurozone countries 7,619,884,851.40
And non Eurozone countries 120,192,083.17
Total EU figure = 7,740,076,934.21
Now take the UK paid up figure 55,509,147.81
Divide the UK figure by the Total EU figure and you get 0.007171
Multiply by 100 and you get the percentage of paid up capital that the UK has in the ECB - 0.7171%
Simples