Viacom-owned premium cable network Showtime, and sister channel the Movie Channel had their best growth year since 1988, said Matt Blank, Showtime Networks Inc. president and chief executive officer.

For 1994, subscriber base grew by 13%, and so far this year it is up another 5%.

While premium cable networks don’t release their subscriber base, the National Cable Television Assn. said Showtime Networks had about 12 million subscribers last year, meaning that its increases are likely putting the Showtime Networks subscribers at just over 14 million. Showtime has the bulk of those subscribers.

Speaking at the semiannual Television Critics Assn. gathering here on July 11, Blank attributed the growth to new technologies such as direct broadcast satellite and an increased willingness by cable operators to promote premium cable networks to their subscribers. Cable operators, facing rate regulations on basic cable networks, have become more aggressive in marketing premium and pay-per-view services to subscribers. This year, Blank said, could be Showtime’s most profitable to date.

The Showtime CEO also said the premium service has enough theatrical product to serve it “well into the next decade.”