(Reuters) – Alphabet’s much-talked about high-speed internet service, Google Fiber, had 53,000 video subscribers as of December end, up 79% from a year earlier, brokerage MoffettNathanson said, citing numbers from the U.S. Copyright Office.

Google googl has been expanding the service, which promises Internet speeds of up to 1,000 megabits per second, in several cities in the United States.

“If there is a surprise here, it is perhaps that the growth rate isn’t higher,” MoffettNathanson said.

“After all, there has been a steady stream of new cities announced, and they’ve now been at it for a long time in at least a handful of markets.”

The service is currently available in Atlanta, Austin, Charlotte, Kansas City, Nashville, Salt Lake City, San Antonio Provo, Utah, and Raleigh-Durham, North Carolina, according to the Google Fiber website.

Alphabet, formerly Google, said in December it would consider bringing the Fiber internet service to Los Angeles and Chicago.