average for sum accumulation in QV 7

[#1]

Hi All,

i have an expression say for e.g. sum(Sales) and it is set to full accumulation.

how do i create a ref line on this chart to show the average on this accumulated sales figure?

i can do it using aggr function but this function doesn't exist in version 7 which my client is using now. is it other way?

thanks!

[#2]

The aggr() function has been available since 7.5.

Phil