Image caption A child being vaccinated in a hospital in Congo

The World Health Organization's annual statistics show progress is being made around the world in cutting child mortality - but it will miss its target of a two-thirds reduction by 2015.

The number of under-fives dying fell from 12 million in 1990 to less than seven million in 2011, the data shows.

But that will not be enough to reach the 2015 Millennium Development Goal.

The WHO says the health gap between countries is narrowing, but there are continuing inequalities in health care.

Many people in low- and middle-income countries have insufficient access to medicines in the public sector, meaning they rely on the private sector, where prices can be up to 16 times higher, says the WHO.

In these countries, an average of only 57% - and in some cases as little as 3% - of selected generic non-branded medicines are available in the public sector, according to data compiled by the global health body.

Key trends in the report Preterm birth is the leading global killer of newborn babies and the second most important cause of death (after pneumonia) in all children aged under five years

Every year about 15 million babies are born before 37 weeks of pregnancy - one million die

Almost 10% of the world's adult population has diabetes

The World Health Statistics 2013 report compares progress made by countries with the best health status and the worst status over two decades, from 1990.

The statistics are compiled from many sources, including government birth and death registrations, hospital records, household surveys and research projects.

"Our statistics show that overall the gaps are closing between the most-advantaged and least-advantaged countries of the world," said Dr Ties Boerma, director of the Department of Health Statistics and Information Systems at the WHO.

"However, the situation is far from satisfactory as progress is uneven and large gaps persist between and within countries."

The gap in child mortality fell, from 171 deaths per 1,000 live births in 1990 to 107 deaths per 1,000 live births in 2011, according to the latest statistics.

Global statistics on the number of women dying in childbirth have also improved, but the WHO says the global decline in maternal deaths (3%) will have to double to meet the goal of reducing maternal deaths by three-quarters.

Commenting on the report, the charity Save the Children said that as well as improving access to healthcare for the poorest families, the world must redouble efforts to tackle hunger, which contributes to a third of child deaths.

"We have made incredible progress in cutting the numbers of children who die every year by improving treatment of preventable diseases and making vaccines available to the poorest children," said Brendan Cox, Save the Children's director of policy.

"But unless we tackle hunger, we risk losing this momentum, and children will continue to die needlessly."