This can easily be accomplished by using JMP's ability to add virtual columns. Assuming your data table has a column that has the percentile value, such as below
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Then open Graph Builder and drag the percentile column to the X axis
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Next, a virtual count variable needs to be created. Right click on the Percentile column and select Formula
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Change the value of the formula from the original column( in my example Percentile), to just the number "1"
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If you right click on the Transform(percentile) column, you can select "Rename" and change the name to whatever you want. I chose the name "Count"
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Close this window and now drag the new virtual column to the Y axis
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Now go to the Points control section and change the Summary Statistic to N
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And then finally right click on the chart, and select Smoother>Remove
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And you will get the final graph
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Jim