One of the major challenges facing developing Asia today is how to provide affordable, adequate, and sustainable old-age income support for a growing elderly population. This is a matter of urgent concern particularly in East and Southeast Asia where countries are at a more advanced stage of the demographic transition from a youthful to an older population.

Published by ADB in September 2012, Pension Systems in East and Southeast Asia: Promoting Fairness and Sustainability looks at the pension systems in eight countries: People's Republic of China (PRC), Indonesia, Republic of Korea, Malaysia, Philippines, Singapore, Thailand, and Viet Nam.

Here's a snapshot, by the numbers, of the key issues discussed in the book.

A rapidly aging population

200 million: The number of senior citizens in the PRC by 2015. The country now has more senior citizens than all European Union countries combined.

15%: The percentage of persons aged 65 and older in Malaysia by 2050, which is triple the 2010 percentage of 4.8%

20 years: The time needed for Viet Nam to make the transition from aging to aged, in comparison to 26 years for Japan and 22 years for Thailand - the two countries that have always been considered to be the most rapidly aging in the region

A question of sustainability

2: The potential support ratio of the working-age population to the retired population in the PRC by 2040. The current ratio stands at 6.

2.7 and 1.7: The ratio of working-age persons to the elderly in Singapore in 2030 and 2050, dropping from 8.2 in 2010

Inequitable systems

14%: The percentage of private formal sector workers that are covered by the pension system in Indonesia. In contrast, the system covers 100% of civil servants and military personnel.

70%: The percentage of people older than 65 who do not receive old-age pensions in the Republic of Korea though, theoretically, coverage is universal in the country

10.4%: The contribution rate of the mandatory pension program for private sector workers in the Philippines, compared with 21% under the scheme for public sector workers. This accounts for the shorter fund life of the private sector scheme.