"Average weekly hours per listener" is a useful figure, which the UK releases.
It seems that talk is higher - some rough comparisons:
BBC Radio 4 = 11.8 hours; LBC = 8.7 hours; BBC Radio Ulster = 10.2 hours
BBC Radio 2 = 10.6 hours; Heart = 6.5 hours; Downtown Radio = 10 hours
And this (the least-readable graph in the world) - on-demand music (OMS) is more than 50% of the total audience from about 11am, and you'd have to assume that individual music radio stations are doing quite poorly.