There’s good news and bad news for Apple. The good news is that the Cupertino-based company sells more tablets in America than anyone. The bad news is that Apple is selling less iPads proportionate to the total share of tablet sales than a year ago… and Mac sales are also going down.

This data comes from the NPD Group, who found that while Apple held a bigger share of tablet sales than anyone else in 2013, that number was down compared to 2012, where it held 17.1% of all tablet sales. Comparatively, it sold only 15.8% of all tablets this year.

Making up the slack? Android and Windows tablets. Android tablet sales are on the rise compared to a year ago, making up 8.7% of all tablet sales compared to just 4.2% a year ago. As for Windows tablet sales, they are up from a scant 0.8% in 2012 to a slightly-less scant 2.2% in 2013.

Macbook sales aren’t much better. In 2012, Apple sold 2.6% of all laptops on the market, but only 1.8% in 2013. That’s a slight dip, but nothing compared to the way Windows notebook sales have plummeted from 42.9% to just 34.1% in 2013. And desktop sales have similarly fallen about 5% in the last year.

The big winner in 2013, according to the NPD Group? Chromebooks. From just 0.2% of all U.S. commercial sales in 2012, the Chromebook line now accounts for 9.6% of all U.S. computer sales. Are Chromebooks the next netbook?

• SourceNPD