(CNN) Marley Dias says she was tired of reading books about "white boys and their dogs" in school.
So at the age of 11, she launched the campaign #1000BlackGirlBooks to identify books featuring people of color as protagonists.
Over the past three years, Dias has collected more than 11,000 books. She is in the process of donating all the books and has given more than half to what she describes as "predominantly black and underserved" communities in the US, Haiti, Ghana, Jamaica and the UK.
The young activist from New Jersey has even gone on to author her own book -- "Marley Dias Gets It Done" -- and is currently developing an app so kids can find "black girl books" more easily.
"I hope that my campaign will mean more opportunities for our stories to be told and for books with black girls as the main character to be put on bookshelves worldwide," she tells CNN.
Yet despite the young writer's best efforts, statistics suggest "black girl books" are still in short supply.
Just 9% of children's books published in the US in 2017 featured African or African American characters -- according to data from the Cooperative Children's Book Center (CCBC) which has been measuring representation in children's books since 1985.
While that figure appears small, it actually represents an improvement on previous years. In 2014, just 5% of children's books recorded by the CCBC included African or African American characters.
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Moreover, CCBC director Kathleen Horning points out that many of the books about black experiences have not been written by authors from that demographic.
Africans and African Americans wrote or illustrated just 3% of the books counted by the CCBC in 2017. Horning says this statistic appears to depict how difficult it can be for black authors to break into the publishing industry.
When children's books about black people do get published, Horning says they often fall into three broad categories: books about slavery, books set during the civil rights movement and books that tell "gritty, contemporary" stories about children growing up in struggling families or teens dealing with violence.
"All of these are important stories, but young readers also want more variety," says Horning. For example, there aren't traditionally "many fantasies with African American characters, or books showing a middle-class black family."
However, Horning adds she has seen flickers of change in 2018, highlighting fantasy book "Children of Blood and Bone" by Toni Adeyemi and "Pride" by Ibi Zoboi, a contemporary remix of "Pride and Prejudice," featuring a Haitian-Dominican-American family.
Others point out that typecasting in children's novels isn't an issue exclusive to the black community.
B.J. Epstein, a lecturer in children's literature at the University of East Anglia in the UK, notes that diverse characters are often pigeonholed by their ethnicity, race, religion, disability or sexual orientation.
In her book "Are the Kids All Right?: Representations of LGBTQ Characters in Children's and Young Adult Literature," Epstein surveyed English books with lesbian, gay, bisexual and transgender characters.
She found the majority of stories dealing with this subject only highlighted the difficulty of coming out, and the negative repercussions associated with doing so.
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The consequences of a lack of diverse characters can extend well beyond the classroom.
"The stories that children read at a young age tell them who matters and who doesn't matter, who's human and who isn't human," explains Philip Nel, professor of English at Kansas State University.
"A story doesn't have to tell us that explicitly. It can tell us that by failing to represent certain groups of people -- omission tells us that these groups of people are not important," Nel adds.
Some classic books still taught in schools contain language and storylines that would be considered overtly racist by today's standards.
But Nel argues that the answer isn't simply removing "problematic" children's classics like Mark Twain's "Adventures of Huckleberry Finn," which uses the N-word 219 times, from school reading lists.
Such stories, "if used carefully, appropriately and in context can be a way to educate people about racism," he says.
Teaching problematic children's classics can allow children of color to critique and disagree with a book, express anger at oppression and find the language to talk about racism while also teaching white children to identify racist ways of thinking and challenge their own racialized assumptions, Nel explains.
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However, he also stressed how critical it was to introduce diverse books in the classroom to provide necessary context.
This is important, particularly in countries like the US, given that approximately 50% of public elementary and secondary school children are non-white, according to data from the National Center for Education Statistics.
According to Horning, the publishing industry desperately needs to diversify.
The 2015 Diversity Baseline Survey of staff at 34 American publishers found 79% of staff to be white.
Publishing groups have sought to address the issue through inclusivity trackers and targets, diversity hiring committees, and mentoring schemes to get people of color into the workforce.
Many publishers also have specific imprints focusing on diverse books for children and young adults.
But it is not only publishers who are responsible for the lack of diverse authors and characters in children's books.
"I think the umbrella here is the adult attitudes have to change," says Horning. "Librarians, teachers and parents have a responsibility to expose children to a wide range of books, and not just channel them into books where they only see themselves reflected."
Epstein agrees that while the industry needs to reform, it is up to teachers and parents to think about the values and morals they pass on to children through the books they read.
"We owe it to our children and to the world they will shape to really think consciously about the books that are available to them," she says.