A former teacher has just graduated from university in Ghana, aged 99.

World War Two veteran Akasease Kofi Boakye Yiadom enrolled at Presbyterian University College's business school aged 96.

"Education has no end," he told CNN. "As far as your brain can work alright, your eyes can see alright, and your ears can hear alright, if you go to school you can learn."

Now he has finished his studies, Boakye Yiadom is urging his classmates to resist the lure of higher salaries overseas and stay in Ghana.

Most say they have no plans to leave. Bright Korang, a fourth-year student at Presbyterian University College, told CNN, "Throughout my education, taxpayers' money has been used to support me.

"Therefore after school I should also help the taxpayer. I can see there are so many opportunities here in Ghana."

But some of his classmates are looking outside the country. Joshua Odame will study for his master's degree in the UK. "The developed countries have the technical know how, so we go and learn and bring it back to the country," he told CNN.

According to the International Organization for Migration (IOM) more than a million Ghanaians migrated from 2000 to 2007, but more than 85 percent return temporarily or permanently.

Leaving the country can yield a windfall for some Ghanaians. A spokesman for the IOM said a 20-fold increase in salaries is possible.

One field that has seen much of its talent exit the country is healthcare. Dr. Mariama Awumbila, head of the center for migration studies at the University of Ghana, said the migration of skilled health workers has had a serious impact on the country.

"In the early 2000s there were quite a number of districts that didn't have a doctor, and some wards didn't even have a nurse," she told CNN.

"In the late 1990s and early 2000s our infant mortality rate increased, and that is associated with the peak of the migration of health professionals."

The "brain drain" has affected many sectors, including financial services, at all levels.

Benjamin Debrah is managing director of Barclays Bank, Ghana. He returned to his home country after working abroad. But moving back to Ghana meant making sacrifices.

"You take a huge pay cut, because wages are lower here," he told CNN.

"You also sacrifice on the levels of certainty. If you are a professional you want to know that if you are right, the outcome will be a particular thing. It's not quite the same in these parts. There is ambiguity."

New graduates share those concerns. Among them is Douglas Darkwah, a senior at the University of Ghana. "We can't stay in the country when [financial] security is not assured," he told CNN.

"I want to make money, to help the poor. [In Ghana] There's no work. There's massive unemployment, so after education there's nothing to do."

Proud of his hard work and survival through hardship, Boakye Yiadom think graduates should stay in the country.

"If it is a scant pay you have to accept it, because it is the government's money that has been used to educate you," he said. "So if you have finished school and passed your degree, you have to stay in Ghana and serve Ghana."

Be there may be a middle ground: Graduates who migrate, and then return to Ghana. Awumbila calls the phenomenon "brain circulation."

"They're contributing and then going back. And they also carry a lot of knowledge back there, so we're circulating the brain," she said.

Migrants are also circulating cash. According to the IOM, the Bank of Ghana estimates that migrant Ghanaians sent $ 1.9 billion back to Ghana in 2008. That's one seventh of Ghana's official exchange rate GDP.

In Boakye Yiadom's room, World War Two pictures are proudly displayed, symbolic of his beliefs: don't leave; fight, and serve the country. And if you do, he says, you might live to a hundred.