You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Guinea-Bissau

Context:
The prevalence of HIV-infection among the adult population is 1.8%. Only 20% of infected pregnant women receive anti retroviral coverage to prevent transmission to newborns.

Question:
How many HIV-infected pregnant women receive retroviral coverage?

20%