a    2017
b    2018
c    Data classified according to ISIC Rev. 4.
d    Estimate.
e    Calculated by the UN Statistics Division from national indices.
f    2016
g    Data classified according to ISIC Rev. 3.
h    2014
i    Areas not elsewhere specified.
j    Data refers to a 5-year period preceding the reference year.
k    2015
l    Refers to foreign citizens.
m    Including refugees.
n    Data as at the end of December.
o    2001
p    2008
q    2009
r    2007
s    Based on R&D budget instead of R&D expenditure.
t    Partial data.
u    Overestimated or based on overestimated data.
v    Break in the time series.
w    2013
x    2004
y    The data for crude oil production include 50 per cent of the output of the Neutral Zone.