MADRID — Rolling off a reputation for cutting edge Yank series and “The Simpsons,” Fox was Spain’s most popular niche channel last year.

The pay TV feed upped daily viewers 23% to an average 1.25 million, for a 4.4% share of theme channel auds, according to research company Corporacion Multimedia.

Spain’s second-rating theme channel by aud share was Sony’s AXN (4%), third was Sogecable’s premium sports/movie service Canal Plus (3.3%), currently only carried by Digital Plus.

Fox’s upped audience rolls off a slowly building market for pay TV in Spain. In December 2007, pay TV took 16.2% share of the total audience, up from 14.5% 12 months earlier.

Of pay TV’s 16.2%, Sogecable satcaster Digital Plus contributed 5.9%, ONO, Spain’s main cabler, 7%; other pay TV systems, including Telefonica’s broadband TV, Imagenio, made up the remaining 3.9%.

The News Corp. weblet also benefits from the continuing popularity of U.S. skeins in Spain. Last year, foreign series, led by “CSI” on broadcaster Telecinco, were watched more than local skeins. Imports took 8.8% of total audience share against 7.3% for home grown fare.

Fox staples include “House,” just starting its fourth season, “Lost,” which has just wrapped its third, and “The Simpsons.” But Fox is also cultivating cult auds for Spanish newbies “Dexter” and “Shark.”