a    2017
b    Amsterdam is the capital and The Hague is the seat of government.
c    2018
d    Data classified according to ISIC Rev. 4.
e    Estimate.
f    2016
g    2014
h    Data refers to a 5-year period preceding the reference year.
i    2015
j    Data as at the end of December.
k    Population aged 16 to 74 years.
l    Users in the last 12 months.
m    Provisional data.
n    2004
o    Development Assistance Committee member (OECD).