HSK Coursebook (HSK规范教程) 6上, p.7.
[Google Translate]: According to statistics from authoritative organizations, in addition to smoking, genetics, etc., infection is also one of the important causes of cancer. 17% of global cancers are caused by infections such as bacteria and viruses, but developed countries account for 7% and developing countries account for 17%. The reason for this difference is that developed countries can prevent infections more efficiently.
I'm trying to understand what the two statistics in bold refer to: 7% of what? 17% of what?
My guess is that it's saying (a) infections cause 17% of global cancers, (b) infections cause 7% of cancers in developing countries, and (c) infections cause 17% of cancers in developed countries. However, this seems mathematically impossible unless there are countries which are neither 发达国家 nor 发展中国家.
Question: What does 发达国家占7％，发展中国家占17％ in the textbook 规范教程HSK6上 refer to?