random sample within strata

[ftr]

Hi,

I have the following problem: I have a large multi country data file 
from which I want to export a random sample of about 20% of the cases of 
each country.

Can I achieve this with the following temporary and the sample commands ?

SORT CASES  by  country.
SPLIT FILE by country.
TEMP.
Sample .2 .
COMPUTE selection = 1.
FREQ selection.
SPLIT FILE OFF


Thanks for any hints.
- ftr