You actually want https://www.measuringworth.com/uscompare/ for the index – as https://www.measuringworth.com/uscompare/relativevalue.php which is the calculator results page. (And it was coded by an Ohio State University college student when it was on EH.Net, before being maintained by me as a college student, before being transferred over to Sam Williamson's personal-business site about ten years ago where it is now – a transfer which I always thought was weird but that's academia for you apparently... regardless, it explains the code quality.)