a    2017
b    Data refers to the urban agglomeration.
c    Estimate.
d    Break in the time series.
e    Provisional data.
f    2014
g    2016
h    2018
i    Data refers to a 5-year period preceding the reference year.
j    2015
k    Including refugees.
l    Refers to foreign citizens.
m    Data as at the end of December.
n    2004
o    2009
p    2001
q    2008
r    2011
s    2013
t    Including nationals residing abroad.