The World Health Organization (WHO) on Thursday said the global life expectancy witnesses "large" gain for children born in 2012 than that born in 1990.

The report, titled "World health statistics 2014" and released by WHO, based on global averages, expected a girl who born in 2012 can live to around 73 years, and a boy to the age of 68.

The annual statistics report showed that low-income countries have made the greatest progress, with an average increase in life expectancy by 9 years from 1990 to 2012, higher than the global average increase level of six.

According to the report, Liberia saw a biggest 20-year life expectancy increase worldwide, followed by Ethiopia, Maldives, Cambodia.

"An important reason why global life expectancy has improved so much is that fewer children are dying before their fifth birthday," Margaret Chan, WHO director general said in a statement.

However, she warned that the major rich-poor divide still existed, people in high-income countries continued to have a much better chance of living longer than people in low-income countries.

Statistics showed a boy born in 2012 in a high-income country could expect to live to the age of around 76, 16 years longer than a boy born in a low-income country. For girls, a gap of 19 years separates life expectancy in high-income (82 years) and low-income countries (63 years).

From the country level, women in Japan have the longest life expectancy in the world at 87 years, followed by Spain, Switzerland and Singapore. Life expectancy among men is 80 years or more in nine countries, with the longest male life expectancy in Iceland, Switzerland and Australia.