a    Projected estimate (medium fertility variant).
b    2015.
c    Mega city.
d    2016.
e    Estimate.
f    Government officials.
g    2014.
h    Data classified according to ISIC Rev. 3.
i    Twelve months ending 30 June of the year stated.
j    2013.
k    Break in the time series.
l    Data refers to a 5-year period preceding the reference year.
m    Including refugees.
n    Data as at the end of December.
o    Data revision.
p    2012.
q    2004.
r    2009.