Here’s a graph for you! It shows the average gap between the year of publication of an issue of Mojo and the year the cover star released their first album. The red line is a trendline of sorts, averaging out 5 years at a time.

As you can see, the gap has been rising pretty steadily – in fact, at a yearly rate. What this means is that time in Mojocoverland – a small fiefdom of Pepperland, somewhere across the Sea Of Dreams – has essentially stood still. Newer groups can make it onto the cover but repeat assignments are rare and since Britpop no new group has managed more than two covers. So there’s no great rate of replacement, but there doesn’t need to be since there’s no real rate of attrition, either: the proportion of covers given to 60s acts isn’t falling.

This isn’t a criticism of Mojo – it’s a magazine which knows its audience and has done very well from it: and as with most music mags the cover is a strategy to entice readers to sample more exotic delights within. When I read the mag regularly its features were well-researched, well-written and a lot more thoughtful than most British music writing.

I decided to look into this stat because I wanted to get a sense of the state of the rock canon. Mojo’s front covers aren’t a proxy for this, but are an interesting place to start. My hypothesis is that one of three things might be happening:

a) A rolling canon: the set of “classic bands” and “classic albums” is based on a moving window of interest and older items gradually drop out to be replaced with newer ones.

b) An expanding canon: older acts and records remain in the canon while new ones are added.

c) A closing canon: older acts and records remain in the canon and the rate of new additions is very low.

In the case of the Mojo covers, you can rule out a) (unless the window is VERY long, which it might be of course), and the truth seems to lie halfway closer to c than b – which is a surprise to me.

Of course, Mojo is a genre-based magazine, so we’re really looking at the ROCK canon here, and as mentioned above, it covers plenty of stuff inside too. And different audiences have different canons, and so on. So this little graph is, on its own, about nothing more than one magazine’s policy.

But the overall question interests me, and it interests me because of the question behind it, which is: how does a popular artform which mythologises its periodic renewals of itself and rejections of its past cope with having such a weighty history?