The proportion of children under five who die each year across the globe has dropped 60 percent over the past four decades, according to a study published Monday.
In the last 20 years this salutary decline has accelerated, with the number of deaths among newborns, infants and one-to-four year olds falling from 11.9 million to an estimated 7.7 million in 2010, the new figures show.
That remains a staggeringly large number of young lives lost, many to preventable diseases and overwhelmingly in the world's poorest nations.
A child born today in Chad, Mali or Nigeria is nearly sixty times less likely to see her or his fifth birthday than one born in Scandinavia.
And progress still falls short of the trajectory needed to meet the UN's Millennium Development goal of slashing child deaths globally by 66 percent between 1990 and 2015.
But the decline in under-five mortality is still an encouraging achievement, and suggests further progress is possible, the report says.
Even at the current rate of improvement, there are 31 countries on pace to meet the UN benchmark for 2015, including Brazil, Mexico, Malaysia and Egypt.
All told, 54 of the 187 nations examined in the study are poised to reach the goal.
In 1970 there were more than 200 under-five deaths for every 1,000 live births, the measure used to rank nations in this grim index.
By 1990, that list had dwindled to 12, and today no country crosses the 200-death threshold, according to the study, published in the British medical journal The Lancet.
"One of the biggest achievements of the past 20 years has been this incredible progress in countries that historically have had the highest child mortality in the world," said Christopher Murray, Director of the University of Washington's Institute for Health Metrics and Evaluation (IHME) and co-author of the study.
"Unlike adult deaths, where we have seen the gap between the countries with the highest mortality and the lowest mortality widen, in child deaths that gap is shrinking," he said in a statement.
The IHME study, based on novel statistical methods, yields a substantially lower estimate than the UN figures which up to now have served as an unchallenged benchmark.
UNICEF, for example, reported 8.77 million under-five deaths in 2008, while the new study estimated 7.95 million for the same year -- a difference of 820,000 lives.
Immunisation, anti-malaria bednets, prevention of mother-to-child HIV transmission, and anti-retroviral drugs have all contributed to the overall decline, the researchers say.
Taken as a whole, industrialised nations have much lower child mortality than developing ones.
But there remain stark differences within the rich-nation club.
Britain has performed most poorly in Europe, its global rank falling from 12th best in 1970 to 33rd in 2010.
Portugal made the most headway over the same period, moving from 74th to 10th -- that is, from 74 to 3.3 deaths per 1,000 live births.
After Singapore, ranked 1st in the world, the lowest estimated under-five mortality rates for 2010 are in Iceland, Sweden, Cyprus and Luxembourg.
In the United States -- whose ranking has dropped from 20th to 42 since 1970 -- the mortality rate is nearly double the European average.
China's ranking of 77th in 2010 is only a modest improvement compared to 20 or 40 years ago, while India's position has remained virtually the same: 146th in 1970 and 140th in 2010.
Several studies from IHME, founded in 2007, have challenged long-standing assumptions about the global health metrics and financing, including a new assessment last month of under-60 adult mortality.