The last time the yearly was extremely overbought at 100, was in 1999, the peak of the dotcom bubble.
Now, 19 years later, we're at the same spot again. Will it correct now, as it did in 1999, or will it stay overbought a few more years? In that case it might rise even more.
It will be interesting to see what will happen, the yearly timeframe is not precise enough for accurate predictions, this was just a super longterm observation which I found interesting.