Complex sentence: In 2007, the World Health Organization (WHO) estimated that globally one-third of males aged 15 years and over are circumcised, with almost 70% of those being Muslims.
Split into simpler sentences: In 2007, the World Health Organization (WHO) estimated that globally, the vast majority of men who are circumcised are Muslims. They estimated 33% of adult males worldwide (aged 15 +) are circumcised, with almost 70% of those being Muslims.