The process of increasing the percentage of elderly population in total population.

The so called old age cut-off is specified after achieving of which the person can be included in the group of elderly population. Most often a uniform age of 60 or 65 is assumed, or a separate age for men (65) and women (60) is introduced. In UN studies a uniform age of 65 for men and women is used.
About ageing of given population say declining number and share of children (0-14 years) and an increase in the number and proportion of older people (65 years and more) in the general population.

• Elderly persons
• Population size
• Age