Girls are more likely to be married off before their eighteenth birthday than enroll in secondary school in an “alarming” 26 countries, a global charity said on Friday.

Niger, where 76 percent of girls marry before they turn 18 and only 10 percent enroll in secondary school, topped the list compiled by CARE International, followed by Chad, Central African Republic, South Sudan and Somalia.

“Girls shouldn’t be walking down the aisle in greater numbers than into secondary school classrooms,” Helen Pankhurst of CARE International said in a statement.

“Every time a girl under 18 is forced into a marriage or prevented from attending school, it’s a missed opportunity to improve that girl’s life and strike at the roots of poverty.”

Child marriage deprives girls of education and opportunities and puts them at risk of serious injury or death if they have children before their bodies are ready. They are also more vulnerable to domestic and sexual violence.

Although many countries have closed the gender gap in primary education, they still have significant gaps when it comes to secondary education, said CARE in a report published ahead of International Day of the Girl Child.

Each day about 39,000 girls worldwide are forced to marry, said CARE, citing United Nations figures. Meanwhile, 62 million girls are not in school, half of them adolescents.

Some of the underlying causes of child marriage, such as poverty and gender discrimination, apply across countries. Others are more localised, like trafficking of girls in Mauritania, dowry considerations in Bangladesh or conflicts in Afghanistan and Mali, CARE said.

In June, the U.N. Human Rights Council adopted a resolution calling for an end to child, early and forced marriage, and recognising child marriage as a violation of human rights.

Ending child marriage by 2030 is one of the targets contained in the new Sustainable Development Goals (SDGs) adopted by world leaders at a U.N. summit in September.