Sorry if this is a rudimentary for all you LEED guru's out there, but I am hoping you can clarify the question I have on a number of items we are specifying for our first LEED project

We are specifying a Chair Lift which is manufactured within 10 miles of our project site. The manufacturer buys components from all over the country and in some cases other countries. As it turns out there are 10 major components, 6 come from within 500 miles, 4 come from outside the 500 mile radius.

How do I calculate the contribution toward this credit?