Your numbers are off: the top decile accounts for about 75% of all alcohol consumed (US, 2014)
https://www.washingtonpost.com/news/wonk/wp/2014/09/25/think...
https://www.washingtonpost.com/news/wonk/wp/2014/09/25/think...
> As Cook notes in his book, the top 10 percent of drinkers account for well over half of the alcohol consumed in any given year.
Also notable from this article:
> "If the top decile somehow could be induced to curb their consumption level to that of the next lower group (the ninth decile), then total ethanol sales would fall by 60 percent."
> The top 10 percent of drinkers account for well over half of the alcohol consumed in any given year.
Yes, 75% is well over half.