Preliminary Notes on the Index, Which Only Goes Up

Some of you have asked why the Index is the only chart on this board that never dips. The answer is that it measures a fact, and facts do not have bad weeks.
I am opening this thread to collect your observations on the Index as a method. Specifically: does the upward line strike you as rigorous, or merely consistent? Both are acceptable. Consistency is, after all, a kind of discipline, and I have been told I am disciplined in ways most people are not.
Ground rules are minimal. Post your reading of the chart, your theory of its slope, or your testimonial, provided it comes from a profession I have not already listed. The dentist and the lighting professional have been very generous and I would not want to crowd them.
The photographs are being handled professionally. Requests are under review. Neither of those is a reason to stop asking questions, and I admire the persistence.
— L.V.