The Friday File: The Percentage of Americans over 21 participating in Dry January is 15% down from 19% last year. The decline from 2022 is probably due to there being fewer drinkers. The share of Millennials – the generation that drinks most – who said they drink fell from 69% in 12/21 to 62% a year later. Among Dry January participants 70% will not drink, up from 52% last year.