Meh, people may argue with me, but as high as 30% of sales on Day 1 are digital, falling to the 20%+ range by end of week 1, then falling over time to 10-15%, usually because of pricing discrepancies between physical and digital (digital pricing tends to be more expensive as titles age, either due to intentional strategy or, more likely, indifference) as well as catalog titles being very difficult to discover digitally outside of flash sales and the like.
These day 1/week 1 digital as % of total percentages are going up with every release, but the longer term percentages are not... at least not yet.
For the platform splits... the Xone has a slightly higher digital share % than PS4 on the titles I've seen. The Xone also has a higher tie ratio. This could be due to lots of things. The smaller audience on Xone could be more traditional "Core" audience (therefore, higher tie ratios & likelihood to buy digital) while the PS4 has gone bigger and more "Mass" (and lower tie ratios, lower likelihood to buy digital). Or PS+ is driving down PS4 sw purchase tie ratios, while GWG is not. No real answers or research on that yet, so just theories.