a    2017
b    Data classified according to ISIC Rev. 4.
c    Estimate.
d    2018
e    2016
f    Excluding water and waste management.
g    2014
h    Data refers to a 5-year period preceding the reference year.
i    2015
j    Refers to foreign citizens.
k    Data as at the end of December.
l    Population aged 16 to 74 years.
m    Users in the last 3 months.
n    Provisional data.
o    2004
p    Development Assistance Committee member (OECD).