Mercurius
Legend
Assuming you're going on yearly average, that would be correct imo, although, again, it depends upon what you are counting and if you are considering page count (as you discussed up-thread).Not quite, 3.0 edition also had a relatively low product count. 1st edition is also an oddity since the release pace changed quite a bit between 1977 and 1988 and that bit of the graph includes B/X and BECMI products.
Ignoring original D&D, B/X and BECMI releases, I'd estimate the order as:
2e > 3.5e > 4e > 3e > 1e > 5e.
For instance, by my accounting, 1E peaked in 1985 with 18 print game products - but only two of those are hardcovers, 1 setting book (Lankhmar) and 14 of them are modules (plus Battlesystem). 3E peaked in 2001 with 17 print game products, but those were mostly longer splat and setting books, so the page count was much higher.
Now if we throw Pathfinder into the mix, P1 probably between 2E and 3.5 and P2 between 3.5 and 4E, or maybe a bit less than 4E. Paizo has churned out a ton of product. I haven't followed them closely, but my sense is that P2 is much diminished, though still substantial.