The popularity of Mohammed would be explained by the fact that quite a lot of people are followers of that imaginary character, whereas there isn’t really a female equivalent for them to idolise, so Muslim girls’ names are a lot more varied.
Mahamuda is the female version of Mohammed.
One of the problems with these surveys is they count all the spelling of Mohammad together but don’t take account of many traditional UK/ European names as also being different spellings of the same name.
For instance Jack, John, Ian, Iain, Evan, Shawn, Sean, Eoin, Ifan, Ivan, Jean, Juan, Hans, Yann, Johan, Giovanni, Gino, Joan, Joanna, Joanne, Jane, Jayne, Janet, Janice, Janis, Jean, Jeane, Jeanne, Jeannie, Hanna, Ivana, Sinead, Seona, Siobhan, Sian are all different spellings of the same name – ?????????? – which is hebrew for ‘God is Gracious’
And while Gods might be imaginary (although that very much depends on what you understand the word God to mean) Mohammad was very definitely a real living, breathing, walking, talking bloke. In no sense imaginary and in no sense imagined to be anything other than long dead by even his most devout followers.