a    2017
b    Refers to Altindag, Cankaya, Etimesgut, Golbasi, Ke├žioren, Mamak, Sincan and Yenimahalle.
c    2018
d    Data classified according to ISIC Rev. 4.
e    Estimate.
f    Provisional data.
g    Break in the time series.
h    2016
i    Excluding water and waste management.
j    2014
k    Data refers to a 5-year period preceding the reference year.
l    2015
m    Including refugees.
n    Data as at the end of December.
o    2004
p    2006
q    2012
r    Users in the last 12 months.
s    Population aged 16 to 74 years.
t    Users in the last 3 months.
u    Turkish citizens resident abroad are included.