the sun and naturally filtered in the upper atmosphere by
the ozone layer; UV radiation can be harmful to living organisms and
has been linked to increasing rates of skin cancer in humans.

Waterborne diseases - those in which bacteria survive in, and are
transmitted through, water; always a serious threat in areas with an
untreated water supply.

Environment - international agreements: This entry separates country
participation in international environmental agreements into two levels
- party to and signed, but not ratified. Agreements are listed in
alphabetical order by the abbreviated form of the full name.

Environmental agreements: This information is presented in Appendix C:
Selected International Environmental Agreements, which includes the
name, abbreviation, date opened for signature, date entered into force,
objective, and parties by category.

Ethnic groups: This entry provides an ordered listing of ethnic groups
starting with the largest and normally includes the percent of total
population.

Exchange rates: This entry provides the official value of a country's
monetary unit at a given date or over a given period of time, as
expressed in units of local currency per US dollar and as determined by
international market forces or official fiat. The International
Organization for Standardization (ISO) 4217 alphabetic currency code
for the national medium of exchange is presented in parenthesis.

Executive branch: This entry includes several subfields. Chief of
state includes the name and title of the titular leader of the country
who represents the state at official and ceremonial functions but may
not be involved with the day-to-day activities of the government. Head
of government includes the name and title of the top administrative
leader who is designated to manage the day-to-day activities of the
government. For example, in the UK, the monarch is the chief of state,
and the prime minister is the head of government. In the US, the
president is both the chief of state and the head of government.
Cabinet includes the official name for this body of high-ranking
advisers and the method for selection of members. Elections include the
nature of election process or accession to power, date of the last
election, and date of the next election. Election results includes the
percent of vote for each candidate in the last election.

Exports: This entry provides the total US dollar amount of merchandise
exp