a    Projected estimate (medium fertility variant).
b    2015.
c    2016.
d    Estimate.
e    2014.
f    Data refers to a 5-year period preceding the reference year.
g    Including refugees.
h    Data as at the end of December.
i    Data revision.
j    2009.
k    2013.
l    2002.
m    Includes inactive subscriptions.
n    Break in the time series.
o    Government only.
p    S&T budget instead of R&D expenditure.
q    2004.
r    Arrivals by air.
s    The arrivals data relate only to three border posts (N'Djili airport in Kinshasa, the Luano airport in Lubumbashi, and the land border-crossing of Kasumbalesa in Katanga province).