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
Then open Graph Builder and drag the percentile column to the X axis
Next, a virtual count variable needs to be created. Right click on the Percentile column and select Formula
Change the value of the formula from the original column( in my example Percentile), to just the number "1"
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"
Close this window and now drag the new virtual column to the Y axis
Now go to the Points control section and change the Summary Statistic to N
And then finally right click on the chart, and select Smoother>Remove
And you will get the final graph
Jim