The most straightforward way to do this is with two columns, each with it's own formula:

Use the Big Class.jmp sample data table and create two columns with the following formulas to see what I mean.

Max height so far = If(Row() == 1, :height, Maximum(:height, :Max Height so far[Row() - 1]))

Proportion of max height so far = :height / :Max Height so far

I'm still working to see if I can do it in a single column.

Jeff

-Jeff