Hollywood bosses have defied the international economic downturn to make summer 2009 the most successful in U.S. box office history – with help from blockbusters including TRANSFORMERS: REVENGE OF THE FALLEN and HARRY POTTER AND THE HALF-BLOOD PRINCE.

Summer box office revenues currently stand at $4.17 billion compared to $4.16 billion takings last year (08) – and film executives expect profits to be boosted further by the upcoming Labor Day holiday on 7 September (09).

According to Daily Variety, movie takings will be up three per cent on 2008.

The numbers have been achieved by a slew of major releases including the latest in the Transformers and Harry Potter franchises, which took $399 million (£249 million), and $294 million (£183 million) at the U.S. box office respectively.

Other highly profitable pictures, which have drawn crowds to movie theatres, include Star Trek, The Proposal, X-Men Origins: Wolverine and surprise hit The Hangover.