Not the best immediate source, but it identifies a study which you can look up if this isn't satisfactory: https://m.huffpost.com/us/entry/us_59fcc5fbe4b0d467d

Not the best immediate source, but it identifies a study which you can look up if this isn't satisfactory: https://m.huffpost.com/us/entry/us_59fcc5fbe4b0d467d4c224b3 https://m.huffpost.com/us/entry/us_59fcc5fbe4b0d467d4c224b3