• by Wendy Davis , Staff Writer @wendyndavis, March 14, 2012

Last month, shortly after news broke that app developers were gathering iPhone users' address books without their permission, Reps. Henry Waxman (D-Calif.) and G.K. Butterfield (D-N.C.) sent Apple CEO Tim Cook a host of questions about how the company enforces privacy guidelines.

The lawmakers wanted to know how many iTunes apps transmit data about users -- including address-book data. Waxman and Butterfield also specifically asked Cook how many of those apps first ask users' permission.

Cook's response didn't include answers to those questions. Instead, in a letter dated March 2 and made public today, the Apple CEO boasted that the company "has an unwavering commitment to giving our customers clear and transparent notice, choice, and control over their personal information."

As far as specific numbers go, Cook said that Apple receives over 26,000 applications for review each week, and rejects approximately 30% that don't comply with its guidelines. "In most cases, the developer addresses the outstanding issue and resubmits the application," Cook said.

He also said that the "vast majority" of the App Store's 550,000 apps don't collect users' data.

Lawmakers now say they want Apple to address concerns at a briefing. "The March 2 reply we received from Apple does not answer a number of the questions we raised about the company's efforts to protect the privacy and security of its mobile device users," Waxman and Butterfield say.

They also say they have new concerns stemming from a report earlier this month that app developers can access iPhone users' photos.

The initial congressional inquiry was sparked by news that a vast array of mobile apps -- including, famously, Path -- gathered data about users' contacts. Lawmakers said the reports raised questions about whether Apple does enough to protect users' privacy.

Cook says in his response that Apple recently worked with Path and other app developers "to ensure that our users receive accurate notice about the developers' request for access to users' address books."