Read this and answer the question. If the question is unanswerable, say "unanswerable".

Beer is sold in bottles and cans; it may also be available on draught, particularly in pubs and bars. The brewing industry is a global business, consisting of several dominant multinational companies and many thousands of smaller producers ranging from brewpubs to regional breweries. The strength of beer is usually around 4% to 6% alcohol by volume (abv), although it may vary between 0.5% and 20%, with some breweries creating examples of 40% abv and above. Beer forms part of the culture of beer-drinking nations and is associated with social traditions such as beer festivals, as well as a rich pub culture involving activities like pub crawling, and pub games such as bar billiards.

What is the strength of beer in pubs?
unanswerable