Oakland, Calif.-based Pandora Media (P) is gaining ground in the U.S. radio market.

On Wednesday, Pandora announced its latest audience metrics for September. Total listener hours in September were up 18% year-over-year to 1.36 billion hours. The number of people listening also increased. Active listeners totaled 72.7 million at month's end, 25% more than at this time last year.

According to company calculations, Pandora now controls a 7.77% market share of the total U.S. radio listening audience -- a 124-basis-point increase over Pandora's market share from September 2012, and 31-b.p. increase from last month.

Pandora shares were up strongly on the news, trading up more than 4% above their Tuesday close as of this writing Wednesday morning. 

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