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:
Newcastle_upon_Tyne

Context:
The Newcastle Beer Festival, organized by CAMRA, takes place in April. In May, Newcastle and Gateshead host the Evolution Festival, a music festival held on the Newcastle and Gateshead Quaysides over the Spring bank holiday, with performances by acts from the world of Rock, Indie and Dance music. The biennial AV Festival of international electronic art, featuring exhibitions, concerts, conferences and film screenings, is held in March. The North East Art Expo, a festival of art and design from the regions professional artists, is held in late May. EAT! NewcastleGateshead, a festival of food and drink, runs for 2 weeks each year in mid June.

Question:
How often is the AV Festival held?

biennial