In 2018, one study noted that the estimated number of young people who identified as transgender ranged between 0.17% and 1.3%.
A 2018 paper  presented the results of North American studies using short (one to three item) self-reports of gender identity and its variance. The studies suggested that 0.17%–1.3% of adolescents and young adults identified as transgender.
Statistics for the transgender population are almost impossible to quantify as different definitions are used to describe the term ”transgender”. We have chosen this study for its reliability and its reasonable understanding of the term “transgender” in the twenty-first century.
 Kaltiala-Heino, R., Bergman, H., Työläjärvi, M., & Frisén, L. (2018). Gender dysphoria in adolescence: current perspectives. Adolescent health, medicine and therapeutics 9, 31–41. [Link]