So I was scanning an old comic (Spider-Woman 37, 1981), scanning allows me to save an electronic copy while passing on the paper copy, and I see that it has circulation figures. Back in those days, the shops ordered as many comics as they thought they could sell and returned the unsold comics to be pulped. Nowadays, they order as many as they think they can sell and how they deal with the extras, well, that's their business. As there's a healthy back issue business (A customer can purchase an issue printed years ago, sometimes an issue will be sold and re-sold a few times), the issues often sell long after their usual time on the shelf has expired.
So I see that for Spider-Woman (Her title was being written by the acclaimed X-Men writer Chris Claremont and drawn by Steve Leiloha*) the average number of an issue printed was a bit over 283,000, the average number of issues actually sold was over 127,000. So I figured, hey, with all of these superhero movies out and with Spider-Woman having been revived (The first series ran from 1978 to 1983 and she started off again in a new series in 2009), the sales for today's Spider-Woman must be pretty good.
I looked at the sales figure for May of this year and was surprised to see that it was a little under 30,000. Granted, it ranked at number 75 out of all the titles and the list had almost 400 titles on it (Knights of the Dinner Table was ranked at 396 with not even 2,500 issues sold, various zombie titles, Grimm Fairy Tales and God Hates Astronauts all sold in the plus-275 rank and all had below-5,000 sales) and the really big-selling titles selling over 500,000 in the case of Secret Wars and almost 150,000 in the case of Star Wars, with issues ranked from six to 16 selling from 120,000 to 80,000. A 1981 issue of the Comics Journal (number 64) shows 109 issues on sale for that month.
As they say, the lead actor is frequently just a handsomer version of the director. Hmm, the artist is half-Hawaiian.
Has the popularity of comics declined or have they stayed about the same? I think one could make a pretty good case that comics have remained roughly the same in popularity and that buyers have just spread out to purchasing many more titles, but as I was told when I tried to sell off some old issues, TV shows, video/computer games and other electronic amusements have bit very deeply into the popularity of printed comics. So I think, overall, superheroes are much more popular, but the actual printed comics are at about the same level of popularity.
Update: It makes sense that price would have an effect. Marvel Comics went for $0.50 in 1981 and go for $3.99 today. The InflationCalculator says $0.50 in today's dollars would be $1.31 now. So Marvel makes an extra $2.68 today, over and above inflation. Is that a good deal for the consumer? Actually it is, as it means both better paper and better printing, but it also probably more than enough to push a comic out of the price range of more casual buyers and thereby lowers the number of issues sold.
*Comics are drawn first by a penciller, who often collaborates closely with the writer, and is then inked so that the lines will show up for the printing plates. The inker can have a serious effect on the finished artwork. Leiloha had been an inker for many years before taking up the pencilling job on Spider-Woman. So although he was new to the job of pencilling, his work was well-known to comics fans