Apple on Thursday said music sales on its iTunes store have topped 5 billion songs, and visitors are renting and purchasing more than 50,000 movies each day.

Apple, which has surpassed Wal-Mart as the leading music retailer in the United States, put out a brief press release on the latest numbers, offering no further details. The company has a catalog of more than 8 million songs, 20,000 TV shows, and 2,000 films, including 350 in high-definition format.

In announcing on April 3 that it had surpassed Wal-Mart, Apple said that it had sold more than 4 billion songs through iTunes. Given that announcement was 77 days ago, that would mean the company has sold nearly 13 million songs a day since then. Apple was not immediately available for comment.

Apple has gotten in trouble before for its iTunes math. In late April, the company said it offered 10 million songs on its 5-year-old store, but later ratcheted the number down to 6 million songs. In August 2007, the company said it had 5 million songs.

Apple's movie collection includes titles from 20th Century Fox, Walt Disney Studios, Paramount Pictures, Warner Bros. Entertainment, Metro-Goldwyn-Mayer Studios, Sony Pictures Television International, and Lionsgate. ITunes will rent and sell movies on the same day as their DVD release. Customers using Mac or Windows operating systems must have iTunes 7.6.2 or higher to buy or rent the movies.

Besides Wal-Mart, Apple's major rivals online include Amazon.com, which has about 5 million songs in its catalog. The retailer has tried to differentiate itself by selling music that's free of digital rights management technology, which means buyers can play the music in any portable media player, such as the Apple iPod or Microsoft Zune. Amazon does not provide the software to play and organize downloads on a PC. Instead, it leverages a customer's available software, such as Apple iTunes.

While the flexibility of DRM-free music sounds appealing, Amazon's music store has had little impact on iTunes. Only 10% of Amazon's MP3 customers had previously bought digital tunes from Apple's online store, according to the NPD Group.