Excel 2000 ... What I have

# of records ... <5000
Col AS ... Formulas producing random numeric values (0 to
20,000,000)

I would like a Formula (Cell AT2) to produce the lowest
value found within the top 80% Volume Total of Col AS.

To do this manually I:

Sort Col AS Descending
Select all values in Col AS to determine Total Sum
Use calculator ... (Total Sum)*(.8)= 80% Volume Total
Select all values in Col AS down to 80% Volume Total
Obtain lowest value from this range
Use above value in another formula

If I could make this happen with a formula in a single
cell ... then I could reference this cell with my formulas
rather than always having to determine & use hard values.

Thanks ... Kha