Your car knows more about you than you think.

DETROIT (AP) -- Your car knows more about you than you think.

Newer cars that connect to the internet can collect vast amounts of data about drivers, such as where you went to dinner, if you broke the speed limit or if your seat belt was buckled.

When you buy a car, you cede data control to your car company. Most automakers say they won't sell information without an owner's consent. But they're not legally required to inform you if they do.

Car data is about to become big business. A new report from consulting firm McKinsey says automotive data could be worth $450 billion to $750 billion globally by 2030. Automakers, insurers, high-tech firms, city planners and advertisers are among those who could use data to refine services. Drivers could share data in exchange for navigation systems, or they could pay extra for perks like a parking spot finder.

Here's a primer on the emerging issue of connected-car data:

Q: Which cars collect data?

A: Just under 20 percent of new cars sold globally now can be linked to the internet, according to BI Intelligence. That figure is expected to reach 75 percent by 2020.

For example, General Motors Co. will have 12 million connected vehicles by the end of this year worldwide, which it says is the most for any automaker.

Q: Do I own data that's collected?