The graying of the world is happening faster than most countries have prepared for.

Seniors over the age of 60 will outnumber children under the age of 15 worldwide for the first time in history by the year 2050.

A study issued by the United Nations warns that the world's population is aging so fast that most countries are not prepared.

When it concerns the social and economic well being of seniors, Sweden comes out on top - Afghanistan the bottom.

In Afghanistan, the life expectancy is 59 years for men and 61 for women.

The global average is 68 for men, 72 for women.