The sizes of the exchange rate adjustment each year are always equal to 5 times the actual period-toperiod
percentage change in the real-world exchange rates for US$, €, Brazilian real, and Sing$
(multiplying the actual % change by 5 is done so as to translate exchange rate changes over the few days
between decision periods into changes that are more representative of a potential full-year change).
However, because actual exchange rate fluctuations are occasionally quite volatile over a several day
period, the maximum exchange rate adjustment during any one period is capped at ±20% (even though
bigger changes over a 12-month period are fairly common in the real world).