a    2017
b    Refers to the official Metropolitan City.
c    2018
d    Data classified according to ISIC Rev. 4.
e    Estimate.
f    Calculated by the UN Statistics Division from national indices.
g    2016
h    Excluding water and waste management.
i    2014
j    Data refers to a 5-year period preceding the reference year.
k    2015
l    Data as at the end of December.
m    Population aged 16 to 74 years.
n    Provisional data.
o    2004
p    Including San Marino.
q    Data include San Marino and the Holy See.
r    Excluding seasonal and border workers.
s    Development Assistance Committee member (OECD).