Page 60 - môc lôc

period. It is the difference between number of in-migrants and number of
out-migrants of a territorial unit on average per 1,000 population of that
territorial unit.

Formula:
I - O
NR (‰) = × 1000
P tb
Where:
NR: Net-migration rate;

I: Number of in-migrants in 12 months prior to the reference period;
O: Number of out-migrants in 12 months prior to the reference period;

P tb: Population up to the reference time-point.
Or: NR = IR - OR

Where:

NR: Net-migration rate;
IR: In-migration rate;

OR: Out-migration rate.
Life expectancy at birth reflects the prospect of a newborn could live
for how many years if the current mortality model is maintained, this is the
key statistical indicator of the Life table.

T
e  0
0
l 0

Where:

e 0: Life expectancy at birth (unit: year);

T 0: Total number of years of the newborns in the Life table who will
continue to live;
l 0: Number of persons who live to the age of 0 of the Life table (the
set of original newborns is observed).

Life expectancy at birth is one of the integrated indicators calculated
from the Life table.

59