a    Projected estimate (medium fertility variant).
b    Land area only.
c    2015.
d    2016.
e    Estimate.
f    2014.
g    Data include oil and gas. The value of oil exports and total exports are rough estimates based on information published in various petroleum industry journals.
h    Year ending 20 March of the year stated.
i    Data refers to a 5-year period preceding the reference year.
j    Including refugees.
k    Data as at the end of December.
l    Exchange rate changed in 2002 from multiple to a managed floating exchange rate. Inter-bank market rate used prior to 2002.
m    Data as at the end of October.
n    Population aged 6 years and over.
o    Excluding government.
p    Excluding private non-profit.
q    2012.
r    2004.