Running Average Single Position

none at all. fucking good idea, mind.

you can work it out for yourself with something like Guiness Book Of British Hit Singles which lists songs highest position and weeks on the chart...only it wont tell you where the song was each and every week...Guiness also do a book that lists the Top 20 or 40 for every week so combined with that you could do it maybe

I seem to recall there was a (UK) book which did something a bit like this - it published month-by-month Top 30 or 40 singles. Its charts may of course have been based on sales for the month overall, but I'm pretty sure it was based on "staying power" in the sense that you mean. Can't remember the title, sorry. Not seen any new editions recently either.

In Guiness a few years ago they did a top 100 singles based on chart performance not just limited to highest position but also on staying power and competition. Fuck knows how they did it but "Relax" was at number one.