According to a long-range study, around 6% of children in the population are gender variant.
Epidemiological study  based on data from 1983-2007 shows that 6% of children in the population are gender variant.
 Steensma, T.D., van der Ende, J., Verhulst, F.C. & Cohen‐Kettenis, P.T. (2013). Gender Variance in Childhood and Sexual Orientation in Adulthood: A Prospective Study. J Sex Med 10 (11): 2723-2733. [Link]