Passage: X-Men Origins: Wolverine was released on April 29, 2009, in the UK, Denmark, South Africa, and Australia; April 30, 2009 in the Philippines and in the Dominican Republic; and May 1, 2009 in the United States and Canada. A contest was held on the official website to determine the location of the world premiere on April 27. In the end, the Harkins at the Tempe Marketplace in Tempe, Arizona won the premiere.  The release in Mexico was delayed until the end of May due to an outbreak of H1N1 flu in the country. On April 22, nine days before the release of the film, it was reported that X-Men Origins: Wolverine was outselling Iron Man "3-to-1 at the same point in the sales cycle (nine days prior to the film's release)."

Question: When did the release get postponed until?
end of May