Byline: "Study finds one in five new gym users give up by Valentine's day"

Article: "According to a study by Marti Hope Gonzales, ...., about 80 percent of resolutions are forgotten by Valentine's Day."

I think the byline has a typo: *four* in five users give up by Valentine's, or one in five makes it to Valentine's. Unless it's a different study, or I'm failing to understand.