Is tour finally getting younger?

I thought I would share this.

A couple of weeks ago I looked at the current age composition of top 100 (the top-most graph).  One thing that is striking (albeit not surprising) is that the 24-27 age group (shaded area) is weakly represented.  In fact, there are already more players in top 100 from the subsequent 20-23 year group (25) than from the 24-27 group (19).  In contrast, four years ago, when the current 24-27 year olds were 20-23, there were only 10 of them in top 100 (shaded area in the second graph).

Thiem is really the only player from that group that still shows some promise.  The currently second highest ranked player from among them is (or at least was a couple of weeks ago) Cecchinato at #17 (!).

So it appears (sadly) that we are seeing a relatively weak cohort playing in what is typically prime tennis age, but also (more optimistically) that there is more hope waiting behind them.

For comparison, I have also included age distribution from 10, 20, 30, 40 years ago, as well as from 1973 when the ranking started.  We can see that the tour was youngest on average around 1990 and has been aging since then.  However, we may be reaching the limit of this aging.  Top 100 is marginally younger than it was four years ago, and with quite a few youngsters seemingly coming through, as well as a handful of oldies who may well be retiring soon, it may get a little younger still.  I do not see us getting back to average age of around 24-25 anytime soon, but we could get to around 27, which would not be all that far from some sort of long run average.

I thought you had done this subject to death.

Where was Stan at 24-27? What had he achieved? What are Zverev, Rublev, Chung, Tsi achieving now?