i'm sure someone has the official numbers, but i think 18 has a much higher print run, they pretty much knew it'd be a big deal, therefore printed more. At least this is how I remember it. If i'm wrong, someone else feel free to step in.
This is an excellent question, I always heard the print numbers were much lower for the teaser cameos than the books from the full storyline. I would like to see the numbers as well. I have only seen 1 copy of #17 in the wild in twenty years.
Cap City numbers:
MOS #17 - 18,700
#18 - 26,350 (I was off on this one. It does help to explain the prices.)
#19 - 96,700
#20 - 84,250
#21 - 138,050
#22 (regular) - 109,350
#22 (die-cut) - 400,450
Stunning, stunning numbers. DC's marketing plan was absolute brilliance.
The Death of Supes absolutely dominated the comics market from November of 1992 until the spring of 1993.
Supes' numbers were low for most of 1992, MOS in the 20s and high 10s, and then shot up to the 100s and then slowly fell over the course of the next 3 years. MOS wouldn't fall back to the 20s again until late 1995.
Keep in mind, these are Capital City order numbers, and do not include the other Direct Market distributors (Diamond, Heroes World, etc) or the newsstand.
Cap City was about 25% of the market. Puts the numbers for #22 into perspective.
Turok #1 sold 1.75 million copies to the Direct market...and it was only the SIXTH highest selling book of 1993 (MOS #22, Supes #78, Action #687, Adventures #500, 501.)
So, there's no significant difference between #17 and #18.