It used to be stated on the Zooplus website, and until i just checked, I thought it still was. They must have now changed there wording to 'high meat content'.
I think the 4% figure you a referring to, is not the meat content, it is in one case the fat content and in another case the % meat of a certian flavour, for example the crayfish flavour is made of 4% crayfish, the rest of the meat content is from other sources such as chicken.
I will try and find some more infomation for you. I do have a carton here, but there is no english, however, my brothers gf is Sweedish, so I could get you a translation in a couple of days.
...ah okay here we go...
Try this link to a Bozita leaflet.
http://www.bozita.co.uk/pdf/bozita_tetra_recart_cat.pdf
Or follow this link to the Bozita website
Bozita, click where it says "click here for more infomation", then click the leaflet on the right, you will get a pdf file.
On the first page it says up to 93% meat.
I know from the infomation that used to be on zooplus, most flavours are more like 88 or 89% meat, but I guess the must have one flavour as high as 93% to be able to make this statment.