[dba-SQLServer] How do I see actual compression ratios?

I am finding how to see estimated compression ratios, how to setup compression, how to see that 
compression is set etc, but I am not finding how to see the actual compression ratio of data stored 
in a table or index.

Is there a property that stores an average compression actually achieved as the data was stored into 
the table / index?

-- 
John W. Colby
Colby Consulting

Reality is what refuses to go away
when you do not believe in it