London, July 21 (IANS) The sixth instalment of Harry Potter has given Hollywood studio Warner Bros. its seventh No.1 hit of the year and has pushed the studio's domestic gross past the $1 billion mark.

The success of "Harry Potter and the Half-Blood Prince" comes on the heals of the studio's recent comedy "The Hangover", which, with more than $235 million in ticket sales thus far, has become the highest-grossing R-rated comedy ever domestically.

Warner Bros. has said in a statement released Sunday that it is the only studio to earn $1 billion annually for nine consecutive years.