https:///26ZvmxbGbW via @VOANews A survey conducted by the United Nations Children's Fund (UNICEF) indicates that the population of out of school children in Nigeria has risen from 10.5 million to 13.2 million, the highest in the world. Most of these children are in Nigeria's northern states of Borno, Yobe and Adamawa, where Boko Haram insecurities have disrupted academic activities.

The indistinctive chatter of young children playing outdoors is very familiar. The boys are playing football while the girls are jumping around.

Most of the children are out of school while some have never been to school.

Favour Shikaan a mother, is not left out of the fun. She joins the children's play.

But sometimes she worries about her children’s future.

"They are four in number and... two are going to school. The other one is small actually, but even though she's small, she has grown to the stage whereby she can go to school if not the financial...like the two that are going to transport from here to Apo resettlement everyday is not easy because there's no money due to our economy today,” Shikaan said.

Shikaan and her four children fled a Boko Haram onslaught in Borno in 2015 to settle here, in Abuja.

But she can only afford to send two of them to school. The other two help her at home with cooking and cleaning.

Bright Shikaan is eleven years old and has never been to school, yet she says she wants to be a doctor.

"I want to be a doctor in the future,” Bright says. "But now I'm not going to school, I don't know how I'll be a doctor."

According to the United Nations Children's Fund, UNICEF, more than 13 million children like Bright here in Nigeria are out of school.

Most of them are in Nigeria’s northern states of Borno, Yobe and Adamawa, where Boko Haram has been waging a campaign against Western education since 2009.

The group abducted 110 school girls from a school in Dapchi, Yobe State in February this year, but returned the girls one month later and warned their parents never to take their children back to school.

Education psychologist Mayowa Adegbile explains that increasing numbers of out of school children in Nigeria adversely affects economic growth.

"Sixty percent of that population are girls only, and you know when you bring it back home, every girl becomes a mother or a woman who would in turn take care of other children. And for a woman who goes to school it has a ripple effect, an economical ripple effect. When she goes to school, she has education, she gets a job, even if she doesn't have a job... even if it's just basic secondary school education, she can communicate basic English and mathematics,” Adegbile said.

Boko Haram is a major factor contributing to the increase in out of school children in Nigeria, but not the only factor. Some cultural beliefs and practices also play significant role.

Nigeria's budgetary spending on education is not enough to quell the widening gap - only seven percent of Nigeria's $24 billion 2018 budget is earmarked for education.

And so far, there appear to be no new policies to boost education spending. https:///26ZvmxbGbW via @VOANews