Primary source for the 17% number (although dubious considering it was 1,010 people online via Amazon's Mechanical Turk, and to qualify participants were required to be sexually active and enjoy listening to music):
I've noticed a lot of people wearing just one, my kids included. They explained to me that by alternating earbuds they can wear them almost continually.
What percentage of Airpods owners do you reckon _always_ have them inside their ears?