Hello,

I am trying to create a formula that will lookup values in a column and find
those values in another column and then place the value in the row next to it
in a specific cell. So far this works with the formula
(=VLOOKUP(I6,$D$11:$E$223,2)). Now most of the time the value for cell I6
(thru I n) will not be found in the list ($D$11:$E$223) so I want to revise
the formula to do one of two things:

1. Always "interpolate" between points even when an exact match is found in
($D$11:$E$223)

2. When the value for cell I6 (thru I n) is not found then find the values
less than and greater than I6 and interpolate between the two points a value
based on the slope of the function defined by the two sets of corresponding
data.


this is driving me insane!!!! Please help me! I have 20 years of data to
enter and if I do it manually it will take 20 years.