Same here. Only happens when I am literally exhausted from a week of 3 hour sleep. Don't even drink coffee. Been like this for as long as I can remember
I have no idea of the stats but I usually absent jet lag, otherwise being on a weird schedule, or having my mind spinning about something fall asleep quickly.
I do use melatonin but mostly only in conjunction with international travel.
Most normal nights is definitely within 10 min for me. I wouldn’t be surprised if it was less than 5 min.