The statistics will fuel criticism that Iran's Islamic legal code allows children, especially girls, to be married at an inappropriately early age.
While Sharia law states that females can be married as young as nine, a 2002 ruling by the powerful Expediency Council laid down that girls below 13 and boys younger than 15 could only wed with their father's consent and the permission of a court.
However, critics complain that the legal standards in many socially conservative areas for allowing younger marriages are lax while a fundamentalist MP, Mohammad Ali Asfenani, has said Iran has a religious obligation to legally recognise the weddings of girls as young as nine
"As some people may not comply with our current Islamic legal system, we must regard nine as being the appropriate age for a girl to have reached puberty and qualified to get married," Mr Asfenani, chairman of the parliamentary legal and judiciary committee, told Khabar Online. "To do otherwise would be to contradict and challenge Islamic Sharia law."