Amazon.com said on Friday it drew more than 10 million new members to its Prime shipping and digital content service over the holidays. Amazon considers its $99-a-year Prime membership, which confers free two-day shipping and streaming of select movies and songs, essential to driving its growth and margins.

Amazon said customers ordered more than 10 times as many items via same-day delivery this holiday season, compared with a year earlier. It did not reveal figures for Prime Now, the one-hour delivery option unveiled for parts of New York City's Manhattan borough just this month.

"We are working hard to make Prime even better and expanding the recently launched Prime Now to additional cities in 2015," CEO Jeff Bezos said in a statement.

Amazon also said nearly 60 percent of its customers shopped via a mobile device this holiday, and total holiday sales through its smartphone app doubled this year.