Ageing in Asia Pacific and the World, Report 2011:
"The world population will increase likely by 2.5 billion over the next 43 years, passing from the current 6.7 billion to 9.2 billion in 2050.
As a result of declining fertility and increasing longevity, the populations of a growing number of countries are ageing rapidly.
Globally, the number of persons aged 60 years or over is expected to nearly triple, increasing from 673 million in 2005 to 2 billion by 2050.
In the more developed regions, 20% of the population is already aged 60 years or over and that proportion is projected to reach 33% in 2050.
In developing countries as a whole, just 8% of the population is today aged 60 years or over but by 2050, 20% of their population is expected to be in that age range.
Whereas the number of persons aged 80 or over (the oldest-old) is projected to increase nearly five-fold, from 88 million in 2005 to 402 million in 2050.
About half of the oldest-old live in developing countries but that share is expected to reach 71% in 2050.
During 2005-2050, eight countries are expected to account for half of the world‘s projected population increase. This includes India, Pakistan, China, Bangladesh and the US.
Europe has the oldest population, with a median age of nearly 39 years that is expected to reach 47 years in 2050.
Global life expectancy at birth, which is estimated to have risen from 58 years in 1970-1975 to 67 years in 2005-2010, is expected to reach 75 years in 2045-2050.
Today almost 1 in 10 people are over 60 years old. By 2050 the figure will be higher than 1 in 5. Currently 64% of older people live in less developed regions, by 2050 this figure will rise to 80%.
Asia will have the greatest growth in the number of older people between 2005 and 2050 in absolute terms (from 365 million in 2005 to 1.23 billion in 2050).
There are over 81 million elderly people in India.
It is expected that by 2025 this figure will be 177 million and by 2050, about 240 million, or more than one in five persons, will be senior citizens"
Source : http://www.xperientialevents.com/images/pdf/pdf_2011/insights%20and%20statistics%20141011.pdf