Billionaire software baron Bill Gates has made the bold prediction that there will be almost no poor countries left by 2035.

In the sixth annual letter published by the Bill and Melinda Gates Foundation, Mr Gates says that there are already clear signs of progress.

"By almost any measure, the world is better than it has ever been," he wrote in the letter.

"People are living longer, healthier lives. Many nations that were aid recipients are now self-sufficient."

Countries once considered poor, such as China, India, Brazil and even Botswana, now have growing economies, he says.

In Africa more broadly, life expectancy has risen since the 1960s despite the HIV epidemic.

More children are going to school and fewer people are hungry and where health conditions have improved, birth-rates have declined, the letter states.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Listen Duration: 4 minutes 55 seconds 4 m 55 s Poor countries not doomed to stay poor: Bill Gates ( Ashley Hall ) Download 2.3 MB

"You might think that such striking progress would be widely celebrated, but in fact, Melinda and I are struck by how many people think the world is getting worse," Mr Gates says.

Gates outlines three myths blocking progress

Although China and India are seen as the current growth stars, the philanthropist claims about 70 per cent of countries will have a higher per-person income by 2035 than China does now.

Nine out of 10 countries will have average income levels above today's average income in India, he says.

But Bill and Melinda Gates argue three myths are blocking progress; that poor countries are doomed to stay poor, that foreign aid is wasteful and that saving lives will cause over-population.

Those beliefs compromise efforts to bring people out of poverty, save lives and improve working conditions, Mr Gates says.

"If you think aid... hasn't had this huge impact or if you think that things like improving health actually create the over-population... you wouldn't understand why that's the Gates Foundation priority," he said.

Mr Gates says using the current definition of poor, by 2035 there will be almost no poor countries left in the world.

"Most countries have moved into a category I call 'middle income'," he said.

"The idea that the government says something really good will happen when we go on foreign adventures and then it just keeps being very tough - I think that has led to the cynicism."

Past letters by the Gates Foundation have largely focussed on its annual activities, but this year the founders say they set out to do something different.

Mr Gates said he wanted cut through negative headlines and present a positive view of the work being done to reduce global poverty and save lives.

"The typical headline is about the setbacks: the tornado, the regime instability," he said.

"This gradual progress of less children dying, of economies - even in Africa - getting richer and richer, it's not clear when somebody is supposed to learn that because it's not really a standard headline."

Poverty will continue, says Gates

But it is not all smooth sailing according Mr Gates, who cites North Korea as one country that will be held back by war and politics.

He says inequality will continue in every region.

While the percentage of very poor people has more than halved since 1990, 1 billion people still live in extreme poverty.

That is the same point highlighted by aid agency Oxfam International in a recent report that puts into stark relief the global divide between rich and poor.

The report found just 85 people - including Mr Gates - control as much wealth as the poorest half of the global population.

"The biggest danger is that this small group of very wealthy people also capture political power," Oxfam's executive director Winnie Byanyima said.

Inequality and corruption have been blamed for the mass protest movements that have emerged in Brazil, Spain, Turkey and Thailand.