No idea sorry. I'm sceptical about the accuracy anyway and where this precentage is pulled from as I'll sometimes get a sleep that looks to be a high scorer that does average. Then what do you do with multiple sleeps, usually for me it'll break it into two separate ones even though there were maybe 5 mins between each. I sleep in one continuous sleep 90% of the time but two colleagues of mine roughly in that age bracket get 3 segments of sleep because of needing the toilet or going for a chocolate binge (exactly what I do if I wake in the night haha) When I used Sleep for Android I got around 60% deep sleep and with Samsung between 0-5% but an alarming amount with zero. Both must be wrong. I get between 4 and 10 hrs sleep depending on the day and with Samsung Health.
I'm 29 but my scores are terrible I'm not sure why the best I ever got was 90% but I'm getting 40-60% regularly.