Oakland, Calif.-based Pandora (NYSE:P) keeps on growing. On Tuesday, the nation's leading Internet radio service revealed its latest metrics for customer usage.

The number of hours users listened to Pandora through all listening media increased 14% year-over-year to 1.28 billion hours in July. However, more of these hours appeared to be tied to the ears of fewer listeners. Active listeners to the service grew 30% to 71.2 million, but total listening hours growth did not match that pace. Investors, perhaps swayed by this divergence of growth paths, had bid down Pandora shares by more than 2% in Tuesday trading. As of this writing, shares sell for a few pennies above $19.

Regardless, by Pandora's calculations, the company now controls a 7.08% share of the total U.S. radio listening audience -- about 15.5% better than one year ago.