What does stoich mean?

[CSH-HQ]

>We are using here in Brazil 22% of anydre alcohol in our normaly produced
>cars, and there is no report about Lambda reading errors in the fuel systems
>that we use ( Bosch,Marelli and GM).
>The governement are planning to use next month 24-26% to decrease the fuel
>importation ( petrol has increased the price too much).
>Another point is that we are using cars with 100% alcohol a lot of years

And what AFR does the gm ecms marketed there use for the Stoich value?.
Bruce