omic issues. Countries with
young populations (high percentage under age 15) need to invest more in
schools, while countries with older populations (high percentage ages
65 and over) need to invest more in the health sector. The age
structure can also be used to help predict potential political issues.
For example, the rapid growth of a young adult population unable to
find employment can lead to unrest.

Agriculture - products: This entry is an ordered listing of major
crops and products starting with the most important.

Airports: This entry gives the total number of airports or airfields
recognizable from the air. The runway(s) may be paved (concrete or
asphalt surfaces) or unpaved (grass, earth, sand, or gravel surfaces)
but may include closed or abandoned installations. Airports or
airfields that are no longer recognizable (overgrown, no facilities,
etc.) are not included. Note that not all airports have accomodations
for refueling, maintenance, or air traffic control.

Airports - with paved runways: This entry gives the total number of
airports with paved runways (concrete or asphalt surfaces) by length.
For airports with more than one runway, only the longest runway is
included according to the following five groups - (1) over 3,047 m, (2)
2,438 to 3,047 m, (3) 1,524 to 2,437 m, (4) 914 to 1,523 m, and (5)
under 914 m. Only airports with usable runways are included in this
listing. Not all airports have facilities for refueling, maintenance,
or air traffic control.

Airports - with unpaved runways: This entry gives the total number of
airports with unpaved runways (grass, dirt, sand, or gravel surfaces)
by length. For airports with more than one runway, only the longest
runway is included according to the following five groups - (1) over
3,047 m, (2) 2,438 to 3,047 m, (3) 1,524 to 2,437 m, (4) 914 to 1,523
m, and (5) under 914 m. Only airports with usable runways are included
in this listing. Not all airports have facilities for refueling,
maintenance, or air traffic control.

Appendixes: This section includes Factbook-related material by topic.

Area: This entry includes three subfields. Total area is the sum of
all land and water areas delimited by international boundaries and/or
coastlines. Land area is the aggregate of all surfaces delimited by
international boundaries and/or coastlines, excluding inland water
bodies (lakes, reservoirs, rivers). Water area is the sum of the
surfaces of all inland