The office said Harry was followed on the list by Oliver, Jack, Alfie, Charlie, Thomas, Jacob, James, Joshua and William.
Meanwhile, Amelia was followed on the girls' list by Olivia, Lily, Jessica, Emily, Sophie, Ruby, Grace, Ava and Isabella.
"There are a number of possible reasons why the popularity of baby names can change over time," the office said in a release. "The popularity of names can be influenced by names of famous figures or current celebrities and what they name their own babies. However, it is an individual choice which can be influenced by a number of other factors such as the religious, cultural and/or ethnic identities of the parents or the names of family, friends or fictional characters."