African consumers value American products highly and are among the most brand-loyal customers in the world – if you win them over today, they might stay with you for life, says San Francisco-based consultant David Michael.

As many as a dozen African economies are expected to grow by double digits in 2013, according to a report in NationalInterest.org.

While rich in oil, minerals and other natural resources, Africa’s greatest resource is its human capital says Michael, a partner in The Boston Consulting Group, a global management and strategy company.

Africa has a population of more than 1.1 billion compared to China’s 1.3 billion and India’s 1.2 billion. Forward-looking businesses should take note that more than 60 percent of Africa’s population is under age 35, Michael said.

More than half of all African countries are considered working democracies with increased transparency, reduced corruption, improved property-rights protections and the rule of law. Even so, the Wall Street Journal’s 2013 Index of Economic Freedom ranks the economies of just eight North African countries as moderately free or better, while just nine sub-Saharan countries fall in this range, the report said.

The challenges to doing business in Africa are great to be sure, Michael said. The continent’s 1.1 billion residents speak more than 2,100 languages and live in 54 countries in an area larger than China, India, the U.S. and Europe combined.

“Yet we estimate that by the year 2020 the African market will be worth well over $1 trillion. That’s a market well worth pursuing,” he said.