There's no real point in putting a figure to it because sites differ so much. Site A on blue widgets might earn $20 a day from 2000 visitors but a blog on poetry might struggle to make $2.
21% of my visitors come from mobiles and tablets which generates 17% of the Adsense income. Frighteningly high considering I have no idea why one high value term appears in the top five for normal Google but when I look at Google for mobile it appears 31st. That's another variable which would affect any income from Adsense for mobiles.