I think this script is obsolete. Item Inspector displays a table like this but with more features. For one thing you can get the meaning and reading revealed in a popup when you move the mouse over the item. You study your leeches by going over them reciting meaning and reading, and then you check your answer with the popup. Disclosure: I am the author of Item Inspector.
This is what a leech is. In Item Inspector you can finely tune the Leech filter to select the items you consider a leech with a real value. With Dashboad Leech Tables you must choose Integers from a dropdown. This is a much less precise selection.
You may get the script here.