pandora-logo-icon-largeSteaming music company Pandora released some interesting numbers today and apparently the street is eating it up with the stock moving up as much as 21% in after hours trading.

Pandora announced 4Q13 total revenue of $125.1 million, a 54% year-over-year increase — advertising revenue of $109.0 million, a 51% year-over-year increase – subscription and other revenue of $16.1 million, a 74% year-over-year increase.

The bulk of the company’s 4Q13 revenue came from mobile which totaled $80.3 million and grew 111% year over year outpacing the mobile time spent listening growth of 70%.

“We continue to monetize mobile at record levels and exceeded our expectations for the quarter,” stated Joe Kennedy, Chairman & CEO of Pandora. “We closed the year with a record 8% share of total U.S. radio listening and record mobile monetization that cemented our leadership in mobile advertising.”

Fiscal year 2013, total revenue was $427.1 million, a 56% year-over-year increase.  Advertising revenue was $375.2 million, a 56% year-over-year increase.  Subscription and other revenue was $51.9 million, a 51% year-over-year increase.

While revenue seems to growing at around 55% for Pandora, it should be noted that total listener hours grew 70% to 14.01 billion.  That kind of disproportionate growth can’t be good for the company’s bottom line long-term. The one thing that may help turn the tide is the company’s recently completed move to integrate radio ad buying platforms into its music streaming technology.