Applications for birth certificate gender changes have surged since a health code revision that eased the process for transgender New Yorkers, the city Health Department said Thursday.

The city approved 731 applications for birth certificate gender-marker changes since 2015, while only 20 applications were approved in 2014.

Before the code update, applicants needed a legal name change and “convertive” surgery in order to get approval for a gender change on their birth certificates.

About 55% of the applicants, whose ages ranged from 5 to 76, changed their gender from male to female. Forty-one applicants who were under 18 were approved with parental consent, according to the Health Department.

“We will continue to work with the community to recognize and affirm transgender lives, improve our services, reduce stigma and promote the health of all transgender New Yorkers,” Health Commissioner Mary Bassett said in a statement.