Women business leaders in Africa say companies on the continent need to work harder at including female members on their boards, a newreport (pdf) by the African Development Bank (AfDB) reveals.

Africa’s influential financial institution examined the boards of companies that are listed on the stock exchanges of 12 of the largest economies in the region. They found the continental average of women sitting in boardrooms to be 4.6% lower than the global average.

The data shows for the majority of African companies, there is at least one woman board director. Nevertheless, 32.9% of firms have no women on their boards and 33.6% have only one.

Globally, Africa is doing well, trailing only Europe and the US in representation with so-called blue-chip companies, higher than the Asia-Pacific region, South America and the Middle East.

Kenya leads the way on the continent with almost 20% of its companies’ board directors being female, while Africa’s largest economy Nigeria, at 11.5%, is below the continental average of 12.7%.

A business culture where board seats are offered mostly through informal networks, such as family, and a lack of women in senior executive positions are some of the issues AfDB says are contributing to low female representation in boardrooms in some African companies.

Additionally, structural realities, like the fact that in some countries, corporate governance is a relatively new phenomenon in the running of companies, is also a factor, according to the report. This leads to a lack of term limits in the amount of time folks get to spend as members of boards. As a result, with little room for changes, there are less opportunities for women to join as directors.

This article is published in collaboration with Quartz. Publication does not imply endorsement of views by the World Economic Forum.

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Author: Omar Mohammed is a contributing writer at Quartz.

Image: A business woman is seen  in the central business district of Kenya’s capital Nairobi. REUTERS/Thomas Mukoya.