At 81.3 years, the life expectancy at birth of Switzerland's male population is the longest average survival for men in the world, the World Health Organization (WHO) indicated Thursday in its World Health Statistics 2016 report.

Their female counterparts can expect to live up to 85.3 years, compared to 86.8 years for Japanese women who rank first in terms of female life expectancy.

In comparison, Sierra Leone has the world's lowest outlook for both males and females, standing at 49.3 years and 50.8 years respectively.

Averaging 71.4 years for both sexes, global life expectancy at birth has increased by five years between 2000 and 2015, the fastest increase since the 1960s.

Gains also reversed declining trends in the 1990s when life expectancy fell in Africa due to the AIDS epidemic and in Eastern Europe because of the collapse of the Soviet Union, according to the report.

Progress remains highly uneven across regions however.

Findings show that new-borns in 29 high-income countries will live up to an average of 80 years or more, while new-borns in 22 sub-Saharan countries are not expected to exceed the 60-year mark.

"Supporting countries to move towards universal health coverage based on strong primary care is the best thing we can do to make sure no one is left behind," said WHO Director General Margaret Chan in a statement.

The report shows that every year 303,000 women die as a result of pregnancy complications and childbirth, while 5.9 million children do not live to reach their fifth birthday.

Over 10 million people die before the age of 70 due to cardiovascular diseases and cancer.

Road traffic injuries, air pollution caused by cooking fuels and outdoor pollution respectively kill 1.25 million, 4.3 million and 3 million people each year.