and i would say what 大力's suggest for RMB is good.
The market discount for RMB against USD for approximate 0.2% a year, but you can get 4-5% pa. so you get net gain of 4% pa. as compared to holding usd position.
This is a short volatility's model. you presume the currency will go up and down but not one way.
The real life is if you buy GBP at 15.00, (OR 1.9 against usd) you will not win in this 16 years...