Population aging in Kenya has received little consideration from development planners, which is understandable in view of the agrarian nature of Kenya's economy and the attention focused on prevailing high rates of fertility. Percentages of population in older age groups are low even by African standards, and are not expected to rise significantly in the near future. However, these percentages belie a very real increase in numbers of older population, as well as a growing concern about disruptions in the traditional social support structure for elderly citizens.
Slightly more than 5 percent of Kenya's population is aged 55 and over, with only 2 percent in the elderly category of 65 years and over (Table I). Projections to the year 2000 show very modest changes in these percentages, with accelerated increases expected after the tum of the century. Today's median population age (the age that divides a population into numerically equal parts of younger and older persons) of 15.3 years will rise gradually to 17.8 over the next 15 years, and then is projected to jump to 22 years by 2020.
The low proportions of current older population are due primarily to two associated demographic developments at the younger end of the age spectrum: extraordinarily high levels of past fertility and relatively low infant mortality. Kenya's total fertility rate in 1980 was estimated at 7.7 births per woman, one of the highest rates in the world. Data from the 1989 Demographic and Health Survey (Kenya National Council for Population and Development and Institute for Resource Development/Macro Systems, Inc. 1989) show a large decline -to 6.7 births -during the 1980's, attributable at least in part to a rapid spread of contraceptive usage. Still, the momentum from Kenya's past population growth will serve to maintain a youthful society: even assuming a 55-percent decline in fertility between 1990 and 2020, increasing numbers of young mothers will bear increasing numbers of babies, such that the population under age 5 will become successively larger in each of the next 30 years. Population expansion at the youngest ages is further accentuated by declines in infant mortality; each year, proportionally more babies survive the high-risk first year of life.
Against this backdrop of rising numbers of Kenyan youth and working-age population, the percentage of older Kenyans shows little change. But the absolute numbers of older population are beginning to swell. Between 1979 and 1990, the ranks of the 55-and-over age group grew by approximately 315,000 persons. In the next 15 years, the increase will be more than 1 million (Table II), followed by a 2-million increase from 2005 to 2020. Relative gains among the elderly (65+) and the oldest old (75+) will be even greater, with the latter category more than doubling every 15 years. The growth rate of the oldest old now exceeds that of the total population (Figure 1), and will climb to nearly 5