The representation of disability in children's literature is a matter of scholarly research, and particularly since the 1970s. However, disability representation is still a modern issue. A 2011 World Report on Disability conducted by the World Health Organization found that around 15% of the global population, 1 billion people, have a disability, yet in 2019 only 3.4% of children's books had disabled main characters. The quality of disability representation can vary depending on the specific disability portrayed. Even though society has included more diverse characters with disabilities, this representation must be handled with care to avoid promoting existing negative stereotypes. History of disability representation 19th century Professor Ian Davidson and colleagues analyzed the depiction of disabled characters in a collection of 19th children's literature from the Toronto Public Library. The researchers found certain common characteristics of disability representation in 19th-century children's literature: disabled characters rarely appeared as individuals, but are usually depicted as impersonal groups and reduced to five oversimplified categories: the diseased or extremely sick, the "crippled" and "deformed", the blind, the "deaf" or "mute", and the broad category of the "insane" or 'mad". The language used to describe disabled characters was often patronizing or offensive, and disabled characters were often made to suffer and were poorly treated by other characters. Oxford Professor Ann Dowker describes how in many 19th-century books, disability representation was often vague and unclear. This lack of description results in a highly inaccurate depiction of disability that was based heavily on stereotypes. Disability representation was also often tied to moral character. For example, in Katy Did (1872), the main character Katy's disability is depicted as an opportunity presented by God to experience the "School of Pain" through which she will learn important moral lessons. Other disabled characters, such as Tiny Tim in A Christmas Carol (1843), were depicted as saintly and pure. Hans Christian Andersen's work present the opportunity to explore disability representation in 19th-century fairy tales. Dr. Vivian Yenika-Agbaw found that in these fairy tales, the relationship between disabled and non-disabled characters was defined by power imbalances. She argues that these relationships reinforced existing societal hierarchies. In four of Andersen's fairy tales—The Little Mermaid (1837), The Brave Tin Soldier (1838), Little Tiny or Thumbelina (1835), and The Ugly Duckling (1843)—the character's place in the social hierarchy was determined by their disability. In all of these examples the disabled character was portrayed as "other" and