The use of permil (a.k.a. parts per thousand) is a way of expressing ratios in terms of whole numbers. Given a ratio or fraction,
it is converted to a permil-age by multiplying by 1000 and appending a "mil
sign" 
.
For example, if an investment grows from a number 
to a number 
, then 
is 
times as much as 
,
or 1730.8
.
Permil
See also
PercentExplore with Wolfram|Alpha
References
Bringhurst, R. The Elements of Typographic Style, 2nd ed. Point Roberts, WA: Hartley and Marks, p. 283, 1997.Referenced on Wolfram|Alpha
PermilCite this as:
Weisstein, Eric W. "Permil." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/Permil.html